Fitness/Diet Accountability Thread

[timewerx]

Carbs are really being villified inordinately. Carbs in themselves don't cause insulin resistance, and don't directly contribute to diabetes. Carbs are also unlikely to make a person fat, as carbohydrates have a significantly higher thermic effect than fats. Typically, if a person gains weight from foods that are pure carbohydrates, it requires consuming alot of calories through fruit juices or sugar sweetened beverages. Even foods like potatoes or white rice don't have the kind of caloric density to actually cause significant increases in body fat (indeed, potato or rice diets have been actually used to treat diabetes in the past).

High saturated fat intake (not uncommon in so-called "western diets") may be the immediate cause of insulin resistance in many cases. Replacing saturated fat with monounsaturated or polyunsaturated fat is known to improve insulin sensitivity.

I have a relative who does about the same diet as I do and even less calories. High carb rice, mostly veggies with some meat (even similar saturated fat intake as I do which is not much) but she's overweight. Although the problem is mainly from her sedentary lifestyle.

 

[BPPLEE]

It's sustainable if you keep doing what you were doing to lose it. At some point, you'll stop losing weight as your body adjust...but if you keep up the same activity level and diet, you won't gain it back.

It was always 40 pounds. Lose it for summer and gain it back for winter

 

[RDKirk]

Carbs are really being villified inordinately. Carbs in themselves don't cause insulin resistance, and don't directly contribute to diabetes. Carbs are also unlikely to make a person fat, as carbohydrates have a significantly higher thermic effect than fats. Typically, if a person gains weight from foods that are pure carbohydrates, it requires consuming alot of calories through fruit juices or sugar sweetened beverages. Even foods like potatoes or white rice don't have the kind of caloric density to actually cause significant increases in body fat (indeed, potato or rice diets have been actually used to treat diabetes in the past).

High saturated fat intake (not uncommon in so-called "western diets") may be the immediate cause of insulin resistance in many cases. Replacing saturated fat with monounsaturated or polyunsaturated fat is known to improve insulin sensitivity.

The immediate causes of insulin resistance in the American diet (not the "Western diet," but in particular, the American diet) is too much sugar and too frequent eating. Many Americans today consume sugar every waking hour and even more during times of stress.

 

[FireDragon76]

My weight is down to 166 pounds, visceral fat is still trending down. My BMI is now 24.7, which is normal. I look visibly thinner than I did a month or two ago.

Maintaining 100 PAI is challenging. I'm not sure my body can adapt without overtraining- I feel like I might need more calories than what I'm eating, and my watch probably is underestimating calories burned somewhat. Most days I'm walking over 12,000 steps, and my watch says I'm burning about 400-700 additional calories. According to Google Bard, maintaining 100 PAI is roughly equivalent to meeting the government recommendations of 30 minutes of medium intensity cardio 4 times per week, and that seems to be in keeping with my experience as well. Light activity doesn't earn you much, ten minutes of slow walking gives you about half a point, you need to be in at least Zone 2 type training to start making serious points.

Having said all that, I think somebody that eats a low calorie, low saturated fat diet could probably be very healthy from a cardiometabolic perspective with a score of only 50. The difference between 50-100 isn't as extreme as 0-50, in terms of what it does for cardiovascular fitness. And that's in line with what the University of Helsinki researchers found, too, most of the benefits are when people become moderately active. That kind of activity would only require about 15 minutes of medium intensity, zone 2 type exercise per day, or perhaps 30 minutes of slow walking, and would probably be similar to what you'ld get with about 7,000 steps per day.

Today we went to Lake Eola's bike and running trail and we walked about a mile and used the monkey bars and parallel bars. I did some horizontal rows and incline pushups, and I just hung on the monkey bars. I couldn't do a single pull up, sad to say. I always struggled doing any, though. However, hanging is a good restorative exercise and I'm considering getting a pullup bar just to practice that some a few times a week.

 

[FireDragon76]

The immediate causes of insulin resistance in the American diet (not the "Western diet," but in particular, the American diet) is too much sugar and too frequent eating. Many Americans today consume sugar every waking hour and even more during times of stress.

Insulin resistance and diabetes/prediabetes are two separate things. It's possible to have insulin resistance and have normal body mass index, and it's also possible to have significant insulin resistance and not be pre-diabetic. Diet and exercise can influence insulin resistance to some degree, regardless of weight or amount of food consumed.

 

[RDKirk]

Insulin resistance and diabetes/prediabetes are two separate things.

I didn't say anything about diabetes. I also didn't say anything about BMI.

It's possible to have insulin resistance and have normal body mass index, and it's also possible to have significant insulin resistance and not be pre-diabetic. Diet and exercise can influence insulin resistance to some degree, regardless of weight or amount of food consumed.

But who has pre-diabetes or type 2 diabetes without insulin resistance?

 

[FireDragon76]

My weight actually went up to 168 but I think that is due to eating more carbs because I am more physically active. Tape measurements put me at just under 20 percent body fat.

My PAI went up to 140 but I think that's too high to maintain without overtraining. Exercise is starting to not feel so good. While it's possible to go from maintaining below 50 to over 150 relatively quickly, I think a more realistic option would be to progress slowly over half a year. Even 50 is somewhat physically active, while 150 seems to be burning alot of calories. Above 125, even simple mile long walks only earn you about 1 point, and it requires spending at least 10 minutes at 80 percent of your maximum heart rate to earn more than a few activity points.

 

[timewerx]

My weight actually went up to 168 but I think that is due to eating more carbs because I am more physically active. Tape measurements put me at just under 20 percent body fat.

My PAI went up to 140 but I think that's too high to maintain without overtraining. Exercise is starting to not feel so good. While it's possible to go from maintaining below 50 to over 150 relatively quickly, I think a more realistic option would be to progress slowly over half a year. Even 50 is somewhat physically active, while 150 seems to be burning alot of calories. Above 125, even simple mile long walks only earn you about 1 point, and it requires spending at least 10 minutes at 80 percent of your maximum heart rate to earn more than a few activity points.

You may need a fitness coach to determine your max heart rate (MHR. A calculator determined my MHR to around 180 bpm.

But my actual MHR is 210 bpm with 30 second max effort sprinting on the stationary bike.

Do note the actual value of your MHR does not determine level of fitness. There are healthy mildly active, older individuals with higher MHR than myself . It's more of an individual parameter than absolute fitness metric. Although MHR can increase with improved physical fitness, it's not a large increase.

The calculator result of MHR is about useless because most of the time, it's significantly lower than the actual MHR.

This is important to make sure your heart rate zones are accurate. There is a chance you're still working out in Zone 1 instead of Zone 2. You can still lose weight in Zone 1 but Zone 2 will do much more positive adaptations to metabolism, exercise performance, and even strength.

 

[FireDragon76]

You may need a fitness coach to determine your max heart rate (MHR. A calculator determined my MHR to around 180 bpm.

I'm using a calculator, it estimates MHR is about 172-173. So does my watch. I assume it's using a similar formula.

The calculator result of MHR is about useless because most of the time, it's significantly lower than the actual MHR.

This is important to make sure your heart rate zones are accurate. There is a chance you're still working out in Zone 1 instead of Zone 2. You can still lose weight in Zone 1 but Zone 2 will do much more positive adaptations to metabolism, exercise performance, and even strength.

According to one cyclist site's calculations, I should be training at around 126 -138 beats per minute, based on a maximum heart rate of 173, and a resting heart rate of 56. Subjectively, it does seem to be more like zone 2 training. I can hold a conversation, but with alot of difficulty.

I looked over the earlier data from my watch from December, and the workouts I was doing on the treadmill or on an elliptical were on average 10-15 beats per minute less. That produces alot less in terms of activity score. Anything over 109 is considered "moderate" at my particular fitness level with the PAI system, but you don't earn points nearly as fast as pushing the heart rate up to about 128-132 (high intensity doesn't start until 145). So it's not really an effective use of gym time. However, I think it was necessary because I wasn't in the kind of shape to do much more.

The only way I can get my heart rate high in a joint-safe manner is with an elliptical. I am looking around for exercise bike options. One issue I have found is that many of the models sold here just have uncomfortable racing seats, or the posture is tilted too forward. I'm also considering getting a vertical climber, because they don't use up alot of space and are supposed to be an intense form of exercise that's relatively low impact. I'm also shopping around for medicine balls (the prices here are ridiculous on any of that stuff, though... inflation is high).

 

[RDKirk]

I'm using a calculator, it estimates MHR is about 172-173. So does my watch. I assume it's using a similar formula.



According to one cyclist site's calculations, I should be training at around 126 -138 beats per minute, based on a maximum heart rate of 173, and a resting heart rate of 56. Subjectively, it does seem to be more like zone 2 training. I can hold a conversation, but with alot of difficulty.

I looked over the earlier data from my watch from December, and the workouts I was doing on the treadmill or on an elliptical were on average 10-15 beats per minute less. That produces alot less in terms of activity score. Anything over 109 is considered "moderate" at my particular fitness level with the PAI system, but you don't earn points nearly as fast as pushing the heart rate up to about 128-132 (high intensity doesn't start until 145). So it's not really an effective use of gym time. However, I think it was necessary because I wasn't in the kind of shape to do much more.

The only way I can get my heart rate high in a joint-safe manner is with an elliptical. I am looking around for exercise bike options. One issue I have found is that many of the models sold here just have uncomfortable racing seats, or the posture is tilted too forward. I'm also considering getting a vertical climber, because they don't use up alot of space and are supposed to be an intense form of exercise that's relatively low impact. I'm also shopping around for medicine balls (the prices here are ridiculous on any of that stuff, though... inflation is high).

That spare racing seat is what you want; the only part of your body you want on the seat are the "sit" bones of your pelvis. What's probably wrong is the overall fit. Get your tips on fit from a good cycle shop and apply them to the exercise bike. It's a science. Even then, if you're not "average" in height, leg length, torso length, and arm length, there might not be an exercise bike that fits you (road bike frames are available in small, medium, and large...exercise bikes are not).

That said, I prefer an elliptical at home that I've modified to be more bike-like. I removed the uprights and installed handle bars. I've also set the stride length short so I'm making more of a pedaling motion than a gliding motion. I work on speed more than effort, and I work my calves the way I would on a bike.

Back in my cycling days in my 40s, my tested MHR was 210 and my "cruise rate" was 155. That is, I could cycle a 5.5-hour century ride at a constant 155.

I'm not sure what my maximum is right now, at age 70. I think it's in the low 170s...I get into the high 160s during my HIIT, but I'm not blowing chunks of lung at that point and I have a lot of energy afterward, so I can probably get up another 10 bpm.

I'm really paying more attention to recovery. No matter how high I push my heartrate, I want it to drop by 25 bpm or more within a minute of stopping any exercise.

 

[FireDragon76]

That said, I prefer an elliptical at home that I've modified to be more bike-like. I removed the uprights and installed handle bars. I've also set the stride length short so I'm making more of a pedaling motion than a gliding motion. I work on speed more than effort, and I work my calves the way I would on a bike.

That's a good idea. Almost all the work on an elliptical is done in the legs anyways. Now days I rarely bother with the arms on the elliptical at the gym as I find all it does is make my back tired and prevents me from getting the best leg workout.

There are a few inexpensive ellipticals available that have a short 13" stride length and look more like upright pedaling. I have considered one as an option... but most people seem to be going for either walking pads or exercise bikes.

 

[timewerx]

Subjectively, it does seem to be more like zone 2 training. I can hold a conversation, but with alot of difficulty.

Ok, you may actually be in Zone 2. I monitor myself with subjective methods. I don't actually have a fitness watch. I do have the thing you put on your fingers to measure heart rate but is not ideal to use on all workouts and I ended up not using anything at all. I still use it from time to time to log my VO2max.

I'm also considering getting a vertical climber, because they don't use up alot of space and are supposed to be an intense form of exercise that's relatively low impact.

Might be a good idea. Like walking/running upstairs exercise. I think it can also be low intensity depending on setting.

most people seem to be going for either walking pads or exercise bikes.

Exercise bike is smaller and probably from online gaming/racing aspect which can be a very fun, very motivating way to exercise indoors if you like video games.

I'm not sure you can do the same with walking pads but many people run or jog in real life and it makes sense many would buy walking pads to use if it's too inconvenient to run outdoors.

 

[FireDragon76]

That spare racing seat is what you want; the only part of your body you want on the seat are the "sit" bones of your pelvis. What's probably wrong is the overall fit. Get your tips on fit from a good cycle shop and apply them to the exercise bike. It's a science. Even then, if you're not "average" in height, leg length, torso length, and arm length, there might not be an exercise bike that fits you (road bike frames are available in small, medium, and large...exercise bikes are not).

I believe there are two types of exercise bikes out there now. One is the older style, basically the pedals have a direct drive against resistance (either a brake pad or a magnet). The newer style, or "spin bike" is meant to feel more like a real bicycle, and the pedals drive a flywheel through a chain or belt transmission, so that a person can stop pedalling and the bike continues to "spin" (hence the name). Spin bikes are popular for doing high intensity intervals. Air bikes are also popular for intervals, and those are more like the spin bikes in terms of having an actual transmission (except an air bike's transmission turns a fan that resists air).

It took a few days to figure this out. Youtube has been remarkably unhelpful trying to figure anything out about exercise bikes.

I never got into "Spinning" or Pelotons or anything like that. I'm used to the older exercise bikes I grew up with, where people just sat on them and typically pedalled mindlessly for an hour or so at a modest pace. They also typically had more of an upright styling to them in terms of the fit, and didn't imitate anything about racing bikes. Back in the 80's they were very simple, and relatively lightweight, compared to alot of the exercise bikes that are being sold now.

If you're interested in a bike for rehab or steady-state cardio, the older, cheaper, and lighter style is probably the best.

 

[RDKirk]

If you're interested in a bike for rehab or steady-state cardio, the older, cheaper, and lighter style is probably the best.

Not really. Remember that cyclists ride road bikes for hours. One of the things I learned when my bike rides began to stretch beyond three hours is that cycling over its century has been hammered to a science. The seat shape, the clothing, the shoes, every aspect is designed for the human body to be able to cycle with the least discomfort and injury for hours and hours.

 

[timewerx]

They also typically had more of an upright styling to them in terms of the fit, and didn't imitate anything about racing bikes. Back in the 80's they were very simple, and relatively lightweight, compared to alot of the exercise bikes that are being sold now.

If you're interested in a bike for rehab or steady-state cardio, the older, cheaper, and lighter style is probably the best.

Even if your exercise bike is fairly upright in stance, you can still lean forward if you want to by bending your elbows.

You'll see this in spin classes. The idea is to lean forward but without putting your weight on the arms. You only use your arms to balance and stabilize yourself on the bike but mainly using your lower back (core) muscles and glutes to support the weight of your upper body.

Pedaling in such stance will recruit the biggest muscles in the body simultaneously including the glutes and the core muscles. Great for higher intensity sessions without feeling the "burn".

Common mistake in that stance is obviously resting your upper body weight on the arms which disengage the core and the glutes, concentrating the work on the quads which later on can result to soreness.

Unless you have back problems, leaning forward with arms unloaded is the way to go with exercise bikes for higher intensity but with less muscle fatigue.

 

[FireDragon76]

I did another fitness test on the elliptical and my VO2Max rose from 20 to 25. Still very low, but it is progressing. I think part of it is learning to get better at taking the test. Also, continuing to lose weight will probably improve VO2Max over time.

I spent another twenty minutes doing more Zone 2 training. Then I went to the neighboring complex's outdoor fitness area and did some calisthenics and used their outdoor fitness equipment, and I slow walked a few thousand more steps around the track they had around the park. My activity score is up to 152 this week. Not overdoing the intensity is important in being able to exercise nearly every day of the week. Something that didn't occur to me before, when I was more concerned about maximizing my time. But now I've basically made exercise part of my lifestyle.

Tomorrow, being Sunday, will be a rest day.

I think I'm going to have to try to do some serious research on exercise bikes, and become better educated on the subject. Youtube doesn't seem to provide good resources now days for that sort of thing.

Years ago I used a bicycle as basic transportation when I lived in the UK, a 12 speed Raleigh. Upright bikes were the most common style, as they gave good visibility and didn't require alot of athleticism.

 

[timewerx]

I did another fitness test on the elliptical and my VO2Max rose from 20 to 25. Still very low, but it is progressing. I think part of it is learning to get better at taking the test. Also, continuing to lose weight will probably improve VO2Max over time.

I spent another twenty minutes doing more Zone 2 training. Then I went to the neighboring complex's outdoor fitness area and did some calisthenics and used their outdoor fitness equipment, and I slow walked a few thousand more steps around the track they had around the park. My activity score is up to 152 this week. Not overdoing the intensity is important in being able to exercise nearly every day of the week. Something that didn't occur to me before, when I was more concerned about maximizing my time. But now I've basically made exercise part of my lifestyle.

Tomorrow, being Sunday, will be a rest day.

I think I'm going to have to try to do some serious research on exercise bikes, and become better educated on the subject. Youtube doesn't seem to provide good resources now days for that sort of thing.

Years ago I used a bicycle as basic transportation when I lived in the UK, a 12 speed Raleigh. Upright bikes were the most common style, as they gave good visibility and didn't require alot of athleticism.

Not bad, that's nearly the 50th percentile at our age bracket. I used to have a 16 speed Raleigh road bike. Late 80's model I think. Best bike I ever had. If I haven't lost it, I'd still be using it.

Last year, when my VO2max peaked to 86, this is what my weekly workout looked like:

Monday to Wednesday: 3 x 5 minutes HIIT sessions with sprint intervals, Thursday to Friday, 1 x 5 minutes HIIT with sprint. Saturday, ~6 hr Zone 2 bike ride with sprint finish (no sprinting prior to the final 5 miles). Sunday is rest day. No resistance training any day of the week at all.

A total of just under 7 hrs of weekly training. Weekdays are relatively easy and short as you can see.

Previously, I did 1.3 hr cardio Mon to Fri, 2 hr Saturday, Sunday is rest or 1 hr active recovery with cycling. This schedule sometimes went 10 hrs per week but ironically inferior to the results I had with the 7 hr plan (~easy HIIT weekdays and 1 hard Saturday).

Currently, my workout plan is like a hybrid of my old and peak VO2max training with added resistance training due to DIY skating lessons. Eventually, I'm going to reintroduce HIIT+sprint intervals to try to get my VO2max back to peak levels.

One key to maximizing your VO2max as you progress is getting enough recovery and avoiding over-training.

The only way to know you're getting enough recovery is you're hitting your rest heart rate (RHR) at least 1 day of the week. For this you need to know your ACTUAL RHR.

To know your actual RHR, take a 1 week break/rest/recovery from exercise. Don't do any exercise during this period. Only light physical tasks are permitted which can include walking at a slow pace and under 15 minutes at a time.

Measure your rest heart rate first thing in the morning everyday during this 1 week rest period. This means upon waking up in the morning, before you eat breakfast, before you brush your teeth, before you go to the bathroom, sit up on your bed or a couch nearby in a comfortable and relaxed sitting position, wait 5 mins and then measure and log your heart rate. Repeat it day after day during this 1 week rest period. The lowest heart rate measured is your actual RHR.

FYI, your heart rate while sleeping is not the same as RHR or the MinHR used to calculate VO2max. If I used my sleeping HR to calculate my VO2max, it'd be close to breaking the record.

Also note as you get fitter and stronger, you RHR may get lower over time and it is a good thing to get your actual RHR every several weeks which also means 1 week of rest from exercise every several weeks. That is how professional athletes train as well.

 

[BPPLEE]

My weight is down to 166 pounds, visceral fat is still trending down. My BMI is now 24.7, which is normal. I look visibly thinner than I did a month or two ago.

Maintaining 100 PAI is challenging. I'm not sure my body can adapt without overtraining- I feel like I might need more calories than what I'm eating, and my watch probably is underestimating calories burned somewhat. Most days I'm walking over 12,000 steps, and my watch says I'm burning about 400-700 additional calories. According to Google Bard, maintaining 100 PAI is roughly equivalent to meeting the government recommendations of 30 minutes of medium intensity cardio 4 times per week, and that seems to be in keeping with my experience as well. Light activity doesn't earn you much, ten minutes of slow walking gives you about half a point, you need to be in at least Zone 2 type training to start making serious points.

Having said all that, I think somebody that eats a low calorie, low saturated fat diet could probably be very healthy from a cardiometabolic perspective with a score of only 50. The difference between 50-100 isn't as extreme as 0-50, in terms of what it does for cardiovascular fitness. And that's in line with what the University of Helsinki researchers found, too, most of the benefits are when people become moderately active. That kind of activity would only require about 15 minutes of medium intensity, zone 2 type exercise per day, or perhaps 30 minutes of slow walking, and would probably be similar to what you'ld get with about 7,000 steps per day.

Today we went to Lake Eola's bike and running trail and we walked about a mile and used the monkey bars and parallel bars. I did some horizontal rows and incline pushups, and I just hung on the monkey bars. I couldn't do a single pull up, sad to say. I always struggled doing any, though. However, hanging is a good restorative exercise and I'm considering getting a pullup bar just to practice that some a few times a week.

I started a 100 rep routine with the Steel Mace.
I do 3 different moves with the rope, for 60 reps, 20 Kettlebell swings each side with one hand and 30 with 2 hands,
25 Indian Club Swings and then 100 reps with the Mace.
After that I come back and do variations two or three times and each time I finish with 100 reps with the Mace
It’s about 250 reps each cycle (round ). I think I’m going to increase it to 300 reps per round . I may just do the Mace routine 3 times for some of the rounds.
It’s a good upper body workout and pretty good for cardio.

 

[FireDragon76]

Not bad, that's nearly the 50th percentile at our age bracket. I used to have a 16 speed Raleigh road bike. Late 80's model I think. Best bike I ever had. If I haven't lost it, I'd still be using it.

It's my understanding that a VO2Max of 25 is poor for a male in their 40's.

I'm hoping I just don't know how to take the test properly: perhaps I'm not used to that intensity in exercise. I'm not willing to throw in the towel just yet, especially as the number has been improving each time I take the test. Losing more weight should help somewhat, if I understand what VO2Max is correctly. Also, I suspect that further cardio work on my legs should help improve the metabolic health of the muscles over time, so that they don't fatigue as easily.

According to my watch, my resting heart rate is 56-58, which is a good resting heart rate for an adult male. It determines resting heart rate by looking at sleeping heart rates and applying an adjustment to calculate daytime resting heart rate. This method is supposedly more consistent. Resting heart rate has gone down 2 beats per minute on average since December.

Last year, when my VO2max peaked to 86, this is what my weekly workout looked like:

That's very good, you could easily be a good endurance athlete if that is true.

One key to maximizing your VO2max as you progress is getting enough recovery and avoiding over-training.

I plan to have two deload days per week where I only do slow walking, Zone 1 type training, and only earn a few activity points. I only plan to have one high intensity day per week (Saturday), and I don't plan on doing alot of HIIT. I plan on just mostly spending more time in the gym on Zone 2, or spend an hour or two doing additional Zone 1 training to boost activity. Yesterday and today I spent about an hour just walking slow around a small track in a local park (it's not a big park, more like a small fitness area), and I also got in a few miles of slow walking at a local shopping mall that's mostly abandoned.

The only way to know you're getting enough recovery is you're hitting your rest heart rate (RHR) at least 1 day of the week. For this you need to know your ACTUAL RHR.

I've been going by heart rate variability, and just paying attention to how I feel.

For a while, I was pushing too hard chasing activity points, but now I'm getting familiar with how the activity system on my watch works. Instead of trying to make sure I always exceed the 100 point goal, I'm going to try to make sure I don't exceed it by too much in the future, to make sure I'm not overtraining. It's easy for somebody like me to become obsessive about meeting goals, and a system like that can easily lead to overtraining.

FYI, your heart rate while sleeping is not the same as RHR or the MinHR used to calculate VO2max. If I used my sleeping HR to calculate my VO2max, it'd be close to breaking the record.

Like I said, a VO2 Max of 86 is really good, so it's probably not far from the estimate.

 

[timewerx]

According to my watch, my resting heart rate is 56-58, which is a good resting heart rate for an adult male.

That's actually GOOD. If we go by that metric alone, that already puts you at the healthier end of our age bracket.

It's my understanding that a VO2Max of 25 is poor for a male in their 40's.

I'm hoping I just don't know how to take the test properly:

It's possible your VO2max would be higher in reality.

I bet your calculated MHR is throwing the calculations off. Calculated MHR is rarely accurate. To get your actual MHR, you need to consult a fitness coach.

I'm crazy and poor as **** so I got my actual MHR on my own ignoring the risk of heart failure or sudden death. If it sounds there's significant risks involved in getting your actual MHR, there is that's why I'm telling you to consult a fitness coach.

If you don't want go down that route, just add 10 to 15 pts to your calculated MHR. It's usually going to be more accurate and your VO2max will be higher.

Like I said, a VO2 Max of 86 is really good, so it's probably not far from the estimate.

I used the formula 15 x (MHR / RHR). I tested the formula on popular athletes using their published heart rates and VO2max results using expensive machines. The calculated VO2max is only few pts off the expensive machine results, which is pretty accurate.