Question about cortisol and running vs other aerobic activities

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I've wondered about this too. Here's my purely uneducated theory:

I'm not sure cortisol is produced in the same amounts after all aerobic exercise for 40 minutes. I think it depends on the type of exercise. Look at cross country skiers. They are more badas$ in the muscle dept.

Running creates more trauma per minute at the same effort level than pretty much any other exercise due to all the pounding. That's probably why more cortisol is released.

wondering about this too wrote:

I've wondered about this too. Here's my purely uneducated theory:

I'm not sure cortisol is produced in the same amounts after all aerobic exercise for 40 minutes. I think it depends on the type of exercise. Look at cross country skiers. They are more badas$ in the muscle dept.

Running creates more trauma per minute at the same effort level than pretty much any other exercise due to all the pounding. That's probably why more cortisol is released.

That's what I figured as well-the body adapts by losing fat/upper body muscle better with running then by anything else because fat hinders running more then rowing or cycling etc. Perhaps this is a negative aspect of the Alter G treadmill?

Depends on how much cycling you are doing compared to your running. Most TDF riders are very skinny.

One hour of cycling does not equal one hour of running as far as caloric burn or even stress on the muscle itself. If you assume about 100 calories per mile running then you can assume about 30-40 calories per mile cycling....so about 30-40 miles cycling equals about 10 miles running....so about an hour running to about 1.5-2 hours cycling.

Good discussion here:

www.bikeforums.net/archive/index.php/t-7469.html

So, if you are gaining mass it is likely due to two things:

1. Glycogen/water storage. You aren't expending as many calories and are not sweating as much and so you will store more glycogen/water for a while.

2. Retaining/gaining muscle mass. Not running is a great way to gain muscle and strength...:) Cycling presents slightly less cortisol release and less muscle breakdown.

Also, your body will lose fat/muscle in certain areas based on hormonal interactions. If you are releasing huge amounts of cortisol due to running you will produce less testosterone because they both come from the same thing...cholesterol. Now that you are releasing less cortisol your testosterone is likely higher leading to increases in upper body musculature.

Plus....look at how you ride a bike, your weight is on your arms/chest....so you are basically in a semi-isometric contraction.

Alan

I was hoping you would chime in runningart. From what I have seen I burn 100 calories every 2.8 miles...so about 35cal/mile. I'm doing between between 20-35 miles a day, broken up into 2 rides sometimes but usually very hard-around 24-26 mph.

What struck me was the speed at the change-2 weeks and I look very different in the upper body. I feel like I should be on an informercial or something.

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Art - most of the TDF riders are doped to the gills.