Getting exhausted and its relation to calorie burn.

Fyreside wrote: »

haha maybe.. . Seriously though. I'm trying to understand the science of whats going on a bit better. Thanks for the replies tho.

Basically what's going on is that your cardiovascular system is out of shape ... and your leg muscles are probably out of shape too ... and you're working on improving the situation.

Keep at it, it will get better.

Fyreside wrote: »

haha maybe.. . Seriously though. I'm trying to understand the science of whats going on a bit better. Thanks for the replies tho.

You asked specifically about a bike, so my answer is pretty limited to that context. Fellow cyclist here.

The best and most accurate way to measure bike calories outside a lab is with a power meter. A PM is useful for fitness and science purposes, the calories thing is just a side effect of how it works, by measuring work done. Speed = power * all opposing forces. Opposing forces are things like air resistance, gravity, inertia, the rolling resistance in your tires, etc.

Power = torque * cadence.

That last part is important, even to calories, because 1 kJ on a bike = 1 kCal. When you go up a hill at low cadence you're pushing hard on the pedals, when you do low cadence on flat ground catching your breath there's probably very little. Cadence by itself doesn't tell you enough, simply increasing it won't burn more calories unless you keep the pedaling force constant.

Now, there's the science, at least the quick version. It doesn't really answer your question though. When you feel exhausted, soft pedal for a moment until you catch your breath, then continue. Don't try to fight your body into better shape, work with it to get there. You picked the most fun tire of exercise you can do with your clothes on, enjoy it. What you're doing is making you fitter.

lorrpb wrote: »

Good job getting started! It's not going to help to exhaust yourself repeatedly throughout the day and it could hurt you. I hope you've been cleared by the doctor for the level of exercise you're doing. If not, please do!
There's such a thing as pacing, which means gradually building up the volume you can over a period of time. It can be challenging when you're just starting, but you can definitely make steady progress. Do what's right for you, not "someone" else or "everyone" else or "people" in general. I know it's hard when so unfit, but it is important to develop habits that will work for the long run.

^^^ This is great advice. OP, if your goal is to pursue fitness and weight loss, then a steady cycling build up at a moderate (or even easy) pace will serve you well in the long term. Think in terms of increased time, not intensity. Just as in running, cycling endurance comes over time. Pushing hard to exhaustion before your body is acclimated to cycling is very uncomfortable and unnecessary in my view. An alternative approach would be to try to "smooth out" the ride by using your gears to keep your effort steady and allowing you to cycle longer.

If cycling is your main thing, there is a cycling challenge thread which might help keep you going.

http://community.myfitnesspal.com/en/discussion/10602580/october-2017-biking-cycling-bicycling-challenge#latest

I don't experience a huge difference in calorie burn per time interval between a reasonably challenging steady-state intensity activity (i e., not dogging it) and higher intensity (but sub-anaerobic threshold (AT)) session, as measured by heart rate monitor. I can't give you precise numbers off the top of my head, but that difference calorically is way smaller than the difference between couch and steady state!

Plus, I can go longer at steady state (by definition! ), for higher total calorie burn, if I have time. Truly high intensity work, i.e., intervals in/above AT, which I've done at times for training purposes, tend to leave me a little more wrung out for daily life after I do them.

Also, you'll hear people claim some kind of "metabolic rev" from EPOC (excess post-exercise oxygen consumption) from high intensity. When you do the math, that's pretty trivial, a handful of calories . . . even more so when you recognize that you can go longer at steady state.

It's harder to say experientially what the caloric impact of intervals is (very high intensity then recovery, repeated), because a heart rate monitor isn't as good at estimating calories for that. I suspect there isn't much bonus vs. steady state, but I don't know about penalty.

Be aware that many elite athletes who need cardiovascular fitness have done a boatload of steady state work in their athletic training, and still do so as elites. So, you're in good company on your current path.

As a regular person initially building base fitness, I'd argue that what you want is a volume/intensity of exercise that challenges you a little, but still feels fun and makes you happy, and leaves you with a good energy level for the other parts of life. On that scale, it sounds like what you're doing now is exactly right.

You'll evaluate your goals and practices and things evolve. Best wishes!

Machka9 wrote: »

BTW - calculating calories burned is all estimation ... unless you use a power metre. For me, the estimate above falls pretty close with what MFP says (when I choose a realistic light/low/slow option) and also with what Strava says.

When I cycle, I use a Polar heart rate monitor. It gives values that are typically about half to 2/3rds of what MFP estimates. 300-375 per hour is the norm for me if I'm going for it. Generally I average 20-22km/h on a moderately hilly route generally ~40km. This amounts to about 80 calories per 5km at best (my weight is 109kg). Of course you could be a much stronger rider than me.

I also use a Fitbit which gives slightly lower numbers after you take off the maintenance calories for the time concerned, but I'm disillusioned with Fitbit because it gives ridiculously high calorie burns for walking compared to cycling. It also credits me with thousands of steps when I'm riding, even though it correctly identifies the exercise as "Outdoor Bike".

Keep in mind that running is a high impact exercise and cycling is no impact unless you crash. It doesn't tear up your joints there way running does.

My big discovery is that the cardiovascular system adapts to new stresses the fastest, followed by the muscles, and finally the tendons/joints.

You can't rush the adaptation, though I find that the cardio adapts the fastest. It only took a week to adapt to a new pace (keep at a running pace a minute longer than the week before).

However, rest is just as important as the exercise, as you have to give the body time to repair and rebuild.

If you try and rush this process, you could injure yourself and put back progress for months.