Why does a lack of sleep reduce stamina?

[Solus]

I know this question probably can't be answered but I'll ask anyway in case someone knows something I'm unaware of.

Last night I went to sleep at 5:30AM and woke up at 9 AM. Today I went for my recently started three time a week jog. Now of course the predictable happened, I wasn’t able to jog very far, in fact I could barely walk very far. I managed to jog about half a mile,my total distance was only two miles and I was competely exhausted. Normally I can jog more than a mile and I can walk over four miles in my hour workout time without feeling very tired.

I understand that a lack of sleep causes me to have reduced stamina, what I want to know is WHY? It’s interesting to consider that mentally I’m able to function adequately at about 80 to 85% compared to normal. My stamina though is down more than 50%, if I were to compare it to my normal activity. So why does getting three hours of sleep cost me so much more stamina compared to my normal seven to eight hours?

I’ve actually studied sleep I wrote a college research paper on it (undergraduate level). As far as brain activity there are theories as to the function of sleep but no one is exactly sure why it is necessary and there is no strong theory established yet (as I recall).

I’m wondering if there are there any doctors or biologists here that might have insight into the actual mechanisms that causes this reduction in stamina due to a lack of sleep. That’s what interests me. Any average person can tell me a lack sleep will reduce my stamnia the key question to ask is why?

My guess is that restorative theory of sleep must have some merit because my body must be missing some chemicals it would producded with a full night's sleep. Sorry for the long winded post!

 

[casebro]

I think sleep is for the brain's rest. I think the body could re-charge while watching TV, or other physical resting- providing it is no more exiting than the drivel on the boob tube. What were you doing that kept you up til 5:30 AM? Dancing and drinking? Bumping uglies? Working out? or other stimulating activity?

 

[Solus]

I think sleep is for the brain's rest. I think the body could re-charge while watching TV, or other physical resting- providing it is no more exiting than the drivel on the boob tube. What were you doing that kept you up til 5:30 AM? Dancing and drinking? Bumping uglies? Working out? or other stimulating activity?

Nope, just playing Tiger Wood's golf game...

It's more fun than it sounds but obviously not it's not the most physically demanding thing I could be doing. I just couldn't sleep that night.

What wonder I though is why, what chemicals are lacking that made my stamina drop so much?

 

[dakotajudo]

My first thought would be insulin.

There seems to be a connection between sleep deprivation and insulin production (maybe related to metabolic syndrome); IIRC, in relation to gaining weight when you run short on sleep.

With respect to exercise and bioenergetics, there are two classes, roughly, of hormones - insulin, and everything else. Everything else (primarily epinephrine, but including glucagon, growth hormone and thyroxine) has anti-insulin effects; these effects are important in exercise - raising blood sugar and increasing lipolysis, for example.

There's a lot to the role of insulin and anti-insulins in exercise, too much for me to go into here.

But I would start there - less sleep -> more insulin -> less endurance.

 

[Solus]

My first thought would be insulin.

There seems to be a connection between sleep deprivation and insulin production (maybe related to metabolic syndrome); IIRC, in relation to gaining weight when you run short on sleep.

With respect to exercise and bioenergetics, there are two classes, roughly, of hormones - insulin, and everything else. Everything else (primarily epinephrine, but including glucagon, growth hormone and thyroxine) has anti-insulin effects; these effects are important in exercise - raising blood sugar and increasing lipolysis, for example.

There's a lot to the role of insulin and anti-insulins in exercise, too much for me to go into here.

But I would start there - less sleep -> more insulin -> less endurance.

That doesn't make sense though. Insulin allows the cells to take in glucose, I would think an excess of insulin would give you more energy?

I can see a lack of sleep causing a defency in the other hormones such as adrenline, that makes sense in relation to lack of stamnia. But with my layman's knowledge I would think having more inslin in the body would mean more energy I must be missing something...

I Just did a little research. Idiot that I am, I too much inslin results in hypoglycemia. That would make sense then not enough blood suger to go around equals a lack of energy.

So now what I'm wondering is if taking some various hormones and drinking a couple of cokes would remove the loss of stamina from a lack of sleep? Interesting to consider, it would be worth trying on a rat but I don't care to experment on myself.

Next time I need to excise when I haven't slept I'll try drinking a coke first and see how it works.

 

[El Greco]

Last night I went to sleep at 5:30AM and woke up at 9 AM. Today I went for my recently started three time a week jog. Now of course the predictable happened, I wasn’t able to jog very far, in fact I could barely walk very far. I managed to jog about half a mile,my total distance was only two miles and I was competely exhausted. Normally I can jog more than a mile and I can walk over four miles in my hour workout time without feeling very tired.

I understand that a lack of sleep causes me to have reduced stamina, what I want to know is WHY?

If we're talking about seriously disturbed sleep or total lack of it (or successive days of less than adequate sleep), then this would screw up several important biological indexes (like testosterone). But apparently even a few REM phases are adequate for most diurnal rhythms to function almost properly.

In accordance to this and from my personal experience, 3.5 hours of sleep don't seriously affect my performance (and I've tested this many times). This is also true for many top level athletes who report that they have only slept for very few hours before an event because of anxiety/excitement, yet they perform very well the next day.

ETA: This article seems to agree with the above.

 

[Dancing David]

I go with the hormone thing, there are all sorts of regulatory chemicals in our bodies and many revolve around our sleep cycle. Then there is the processing of waste products and the sleep cycle itself.

We all need different levels of sleep as well, and the amount we need will vary from day to day. the imporatnt thing is to try to wake up at the same time every day, that allows the clock to stay set. Some people are also very effected by light and sound. mentaly i need about five hours a day of sleep, but after a week I need to go back to an eight hour sleep.

 

[dakotajudo]

That doesn't make sense though. Insulin allows the cells to take in glucose, I would think an excess of insulin would give you more energy?

I can see a lack of sleep causing a defency in the other hormones such as adrenline, that makes sense in relation to lack of stamnia. But with my layman's knowledge I would think having more inslin in the body would mean more energy I must be missing something...

I Just did a little research. Idiot that I am, I too much inslin results in hypoglycemia. That would make sense then not enough blood suger to go around equals a lack of energy.

Hypoglycemia is just one of the effects of insulin. More importantly with respect to exercise, it alters metabolism inside cells. Simply, insulin tends to make sugars and lipids less available for energy (i.e. glucose -> glycogen).

Like I said earlier, it's pretty complex.

Exercise itself causes hypoglycemia independently of insulin. There are glucose transporters that become active in muscles during contration. One implication of this is that e xercise can be used to moderate the symptoms of diabetes.

But endurance exercise also requires metabolic changes, inside muscle (sustrate utilization), liver (glycogenolysis and gluconeogenesis) and fat cells (lipolysis).

So now what I'm wondering is if taking some various hormones and drinking a couple of cokes would remove the loss of stamina from a lack of sleep? Interesting to consider, it would be worth trying on a rat but I don't care to experment on myself.

Next time I need to excise when I haven't slept I'll try drinking a coke first and see how it works.

Caffeine is a performance enhancing drug, though generally only in caffeine-naive individuals (that is, don't drink coffee regularly). Do a PubMed search on "caffeine" and "exercise" (I'd provide links, but my post count is still a bit low, I think).

Caffiene tends to enhance the effect of epinephrine - which has an anti-insulin effect.

I would go with coffee instead of coke - the sugars might trigger an insulin response independently. Again, that's a bit compolicated as well - the fructose found in high fructose corn syrup alters glucose metabolism. PubMed "high fructose corn syrup" and "metabolic syndrome".

Or mocha - but then, you might get an insulin response. Insulin isn't just sugar metabolism; amino acids and fats also trigger insulin release - and good mocha will have whole milk. Insulin tends to promote anabolism of lipids and amino acids, which is why some body builders use insulin.

So maybe not mocha before exercise. There is research, though, that chocolate milk is a great exercise recovery drink.

ETA: This article seems to agree with the above.

Unfortunately, there's no references on that page, especially to see how they measured endurance performance.

I'm not suprised that short burst performance (i.e. sprints) are not affected. That's been my experience - a good night's sleep two nights before competition is important; the night before, not so much.

But then, for competition, I'd expect to have more circulating epinephrine, as part of the mental state and associated sympathetic activity.

Day to day training, on the other hand, might be more affected. But how do you test that? Does being part of an experiment produce a competition effect?

 

[El Greco]

Unfortunately, there's no references on that page

Effects of a selective sleep deprivation on subsequent anaerobic performance
Effect of sleep deprivation on shuttle run score in middle-aged amateur athletes. Influence of initial score
Influence of time of day and partial sleep loss on muscle strength in eumenorrheic females

There are more.

And a couple that show some endurance performance diminishment, although nowhere near to what Solus describes:
Sleep deprivation and the effect on exercise performance
Disturbance of sports performance after partial sleep deprivation

 

[Hellbound]

Just my uneducated opinion:

Don't discount mental states. From my experience, both in my own traiing and seeing that of others (specifically people new to a particular training activity), 50% of your endurance is tied into your mental state. So being tired mentally can reduce your physical endurance as well...you feel a bit more grumpy and/or tense, disconcerted and unfocused. You lose concentration a bit easier, etc. I'd suspect this would also explain why it seems to be less of an effect for professional athletes, who train under all sorts of conditions and learn to push themselves even when they are mentally off. As applies to myself, there are days when I'm well-rested, but my mental state is off (stress, worry, whatever) and my workout suffers severely. Likewise, there are days I physically don't feel well, but I'm focused and determined, and perform at a level higher than normal.

Just my 2 cents (no refunds...all sales are final...buyer assumes all liability as a result of use of this purchase).

 

[El Greco]

Here's another article that says more or less the same things as the first one, but also includes references.

Don't discount mental states. From my experience, both in my own traiing and seeing that of others (specifically people new to a particular training activity), 50% of your endurance is tied into your mental state.

Yep. From the article above:

The physiological effects of sleep on performance are somewhat remarkable. However, it appears that the importance lies in educating the athlete into understanding that sleep loss or disturbance may not actually become a negative form of preparation for them. It is the psychological aspect and the levels of perceived exertion that need to be addressed prior to competition so that when an athlete experiences sleep deprivation or interruption they are aware of the effects, if any, on their performance.

 

[dakotajudo]

Effects of a selective sleep deprivation on subsequent anaerobic performance
Effect of sleep deprivation on shuttle run score in middle-aged amateur athletes. Influence of initial score
Influence of time of day and partial sleep loss on muscle strength in eumenorrheic females
.etc.

Oh, I could have done a PubMed search myself.

It's just that, in a review of literature, when the reviewer cites results, I'd like to go to the work he's citing, so to see if would make the same interpretation.

The quote I'm thinking of, from the link you provided, is

For example, studies show that if an athlete sleeps only 2.5 hours per night for three consecutive nights, there is absolutely no loss in hand and arm-muscle strength, no decrease in broad jumping ability, no increase in perceived exertion during strenuous exercise, no decline in lung function or respiratory capacity, and - most importantly - no loss of endurance capacity.

Specifically, which studies? Where all the performance measures tested in the same study, or where there multiple studies of 2.5 hours X 3 nights. How did they measure endurance capacity in these studies?

I don't care to search through PubMed and try to track these down.

 

[El Greco]

Specifically, which studies? Where all the performance measures tested in the same study, or where there multiple studies of 2.5 hours X 3 nights. How did they measure endurance capacity in these studies?

That one:

Reilly, T., Deykin, T. 1983. Effects of partial sleep loss on subjective states, psychomotor and physical performance tests. J. Human Movement Studies. 9. pp 157-170.

It doesn't seem to be indexed in Pubmed but still, I could probably find the whole study if you are really interested.

Do you doubt the conclusions in the above articles that are based on this study, and if so, why ?

I don't care to search through PubMed and try to track these down.

Well, good for you.

 

[Solus]

If we're talking about seriously disturbed sleep or total lack of it (or successive days of less than adequate sleep), then this would screw up several important biological indexes (like testosterone). But apparently even a few REM phases are adequate for most diurnal rhythms to function almost properly.

In accordance to this and from my personal experience, 3.5 hours of sleep don't seriously affect my performance (and I've tested this many times). This is also true for many top level athletes who report that they have only slept for very few hours before an event because of anxiety/excitement, yet they perform very well the next day.

ETA: This article seems to agree with the above.

Thanks for the info everyone, this will give me something to read. I need to add though that I"m not anywhere near a top level athlete. In fact I only started my jogging program a few weeks ago. It never tired me out that much but the day I didn't sleep I felt like I could fall over just from only 2 miles. I guess a more fit person would be less affected by lack of sleep.

I'll read more about this and comment when I have sometime later.