T Nation

Caloric Expendature of Mental Work.

Okay this may not be the most relevant topic to training, but I have to ask because its driving me insane.

How much does mental work affect the number of calories you burn. I ask b/c I’ve noticed that when I go through any period of time where I have to think, I’m constantly hungry. I typically lose 5-10 lbs during midterms and finals with the same diet going in, usually more. I can’t tell if this is stress or not…

A couple googles has left me with no answers. Do any of you know?

[quote]CarvedInsane wrote:
Okay this may not be the most relevant topic to training, but I have to ask because its driving me insane.

How much does mental work affect the number of calories you burn. I ask b/c I’ve noticed that when I go through any period of time where I have to think, I’m constantly hungry. I typically lose 5-10 lbs during midterms and finals with the same diet going in, usually more. I can’t tell if this is stress or not…

A couple googles has left me with no answers. Do any of you know? [/quote]
This is probably more stress related than anything.

I don’t usually make much progress around midterms or finals either.

Stress and lack of sleep.

Although the brain represents only 2% of the body weight, it receives 15% of the cardiac output, 20% of total body oxygen consumption, and 25% of total body glucose utilization.

ACKNOWLEDGMENTS

Research in the laboratory of PJM is supported by a grant from Fonds National Suisse de la Recherche Scientifique (31-26427.89). The authors are grateful to Ms. M. Emch for expert secretarial help.

P. J. Magistretti, L. Pellerin, and J.-L. Martin: Institut de Physiologie, Facult? de M?decine, Universit? de Lausanne, CH 1005 Lausanne, Switzerland

Though the brain is a drain, I don’t think you’ll find the variance is all that much.

Many many people sit at a desk and think all day, and they aren’t wasting away!!!

And no, this doesn’t necessarily mean they are slacking off… :wink:

This does bring up an interesting idea. Can I burn calories just thinking about working out? Do I burn more calories thinking about deadlifts than I do thinking about curls?

Anyhow, to get back to your original question I really do not think that thinking burns many calories. The majority of your mental processes are not conscious, but unconscious. This is true whether you are thinking, sleeping, or working out. Since this is true, the majority of the calorie burning potential is not under direct control. So, even if the brain had the ability to burn a lot of calories (which doesn’t seem probable) very little of it would be under your control anyway.

So, why do you lose weight during finals. Stress probably has something to do with it. Lack of sleep, often common during exam time, is also very hard on the body.

Right. I understand stress, and resulting cortisol, etc. and I always get my 8 hours, regardless of workload. I’ve thought of all that.

It doesn’t explain why I am hungry every hour, even after a large meal. I can eat a 1000 cal meal and get hunger pangs less than an hour later. I am also losing wieght while eating like this, where as I would normally be gaining, too quickly at that.

I’m also not talking about normal thought, I’m talking about engulfing deep focused thought. Absorb 400-500pages/day and retain 85% of it thought. These are the times when I feel like it is affecting me.

[quote]BigDaddyT wrote:
This does bring up an interesting idea. Can I burn calories just thinking about working out? Do I burn more calories thinking about deadlifts than I do thinking about curls?
[/quote]

There’s a study somewhere about this, showed up on one of the googles I mentioned. Thinking about exercise can result in wieght loss. Subconscious suggestion maybe? I’m not sure about all that though.

[quote]dhuge67 wrote:
CarvedInsane wrote:
Okay this may not be the most relevant topic to training, but I have to ask because its driving me insane.

How much does mental work affect the number of calories you burn. I ask b/c I’ve noticed that when I go through any period of time where I have to think, I’m constantly hungry. I typically lose 5-10 lbs during midterms and finals with the same diet going in, usually more. I can’t tell if this is stress or not…

A couple googles has left me with no answers. Do any of you know?
This is probably more stress related than anything.
[/quote]

I second that. during exams/end of term essays I drop significant weight. I remedy this by taking naps and eating lots of shit food (poptarts, wendy’s, cookies, lots of carbs).

[quote]keaster wrote:
dhuge67 wrote:
CarvedInsane wrote:
Okay this may not be the most relevant topic to training, but I have to ask because its driving me insane.

How much does mental work affect the number of calories you burn. I ask b/c I’ve noticed that when I go through any period of time where I have to think, I’m constantly hungry. I typically lose 5-10 lbs during midterms and finals with the same diet going in, usually more. I can’t tell if this is stress or not…

A couple googles has left me with no answers. Do any of you know?
This is probably more stress related than anything.

I second that. during exams/end of term essays I drop significant weight. I remedy this by taking naps and eating lots of shit food (poptarts, wendy’s, cookies, lots of carbs).

[/quote]

I’ve noticed this too. But I try to stay away from crappy carbs near test time. I’ve found that the healthier I eat, the better and more awake I feel during tests. Crappy food takes the edge off for me.

[quote]CarvedInsane wrote:
Right. I understand stress, and resulting cortisol, etc. and I always get my 8 hours, regardless of workload. I’ve thought of all that.

It doesn’t explain why I am hungry every hour, even after a large meal… [/quote]

Maybe we are thinking about the definition of ‘stress’ differently. Stress is not just emotional anxiety, stress would also raise your heart rate and increase your metabolism, increase adrenalin in your system, etc. Make sense?

Theoretically, training with weights is a form of stress. Highly organized, deliberate, and measurable, sure. But lifting weights is a stress on the body, with the goal of creating a physical compensation.

One of the T-Nation writers (Christian maybe?) described training as an “irritant” to the body. I’d say that gearing up for a big final exam would also create a mild irritant effect, not as much as a weight training session of course, but enough to notice a difference.