Field of Science

Exercise

I'm not one for high performance exercise and I definitely wouldn't be found in a sports team. In fact I've rarely set foot in a gym other than to sit an exam.

I personally hate gyms as they smell of B.O. and are full of males looking at themselves in the mirror whilst trying to 'pick-up' girls. This made me cringe and want to vomit..
As for sport teams? I joined the Hockey and Rowing teams at university during my undergraduate. I found this pointless as both sports lived by the rule 'Only the cool girls who worship the seniors will actually get in the team.' Unfortunately if you were like me and wasn't deemed 'cool enough' you were shoved to the back, forgotten about and was just one of those girls who went to training.

This probably makes me sound like an incredibly un-fit, cynical about sports individual who sits at home watching soaps in the evening. Well, the watching soaps part is right, but I do have TWO highly demanding Labradors who go mental and start jumping around like frogs when you even mention the word 'walkies'.
Therefore I spend most my evenings doing the one physical education sport I pretty much hated at high school.. 'cross-country'.
This daily activity has, however, grown on me and I much prefer running in the countryside, in the fresh air than in a hot sweaty room in the gym. Also with 2 dogs you don't feel too insane when you start talking to yourself, obviously...you're talking to the dogs!

So exercise doesn't need to involve you having to endure the gym, I find running in the country waaay better!

This is all good, in fact exercise releases dopamine (the happy neurotransmitter) that gives us a sense of satisfaction, reward, energy and the 'feel good' factor, making exercise to seem like a real reward.
I have been a victim to the 'feel good' factor.. I went running and to the gym every day for a week after a nasty 'break-up'. My flat mates thought I was drunk when I returned in the evenings, in a way I suppose I was.. drunk on dopamine!

A nice image to show how these 3 main neurotransmitters act (norepinephrine=noradrenaline, synthesised from dopamine http://www.weightgaintips.net/images/norepinephrine-dopamine-serotonin.gif)

I'm sure most of you have felt like this after a good session, however after a certain time period dopamine levels decrease and seratonin levels rise (the not so happy neurotransmitter). Serotonin is responsible for sleep, muscle contraction, obsessions, anxiety and mood. Therefore with an increase in muscle contraction it makes sense serotonin increases during excersise. However, it is a target for anti-depressant drugs and was hypothesised to be responsible for chronic fatigue syndrome (Meeusen. R, Watson. P et al. 2006). It also explains the obsession with excersise that some people get (my one week binge!). However, serotonin has been found to have little effect on fatigue in tests and dopamine is thought to have more of an effect(Meeusen. R, Watson. P et al. 2006).

So for all you budding athletes, something that prevents dopamine from re-uptake and decreasing could keep you possibly excersising for longer? Well tests have been done, and at 18degrees there was no improvement! (Roelands. B, Hasegawa. H et al. 2008). So, the happy neurotransmitter alone obviously isn't responsible for us not fatiguing.
However, at 30degrees the dopamine re-uptake inhibitor allowed athletes to perform 16% longer than the control (Roelands. B, Hasegawa. H et al. 2008). So if we have this drug then we can perform longer in the heat? Yes and no. This study shows at fatigue your core temperature reaches 40degrees, if you pro-long this time with drugs then it could cause heat related illness, that could result in death (Roelands. B, Hasegawa. H et al. 2008).

So, if you had a dopamine re-uptake inhibitor you could exercise for longer in the heat, however in cool conditions we can excersise for longer as there's more heat exchange between our body and the environment (Maughan. R. J, Shirreffs. S. M. and Watson. P 2007), therefore cooling us down more effectively so it takes longer to get to the magic fatigue temperature of 40degrees.
This is why you can often exercise longer in the winter than the summer! Pretty interesting? So if your wanting to excerise for longer, dont jump for drugs as that's stupid! Just lower your temperature, or excerise when it's cool outside. I know i'll be taking the heat advice (as well as drinking lots of fluids, which also cool the body and provide nutrients) when I hopefully participate in the cancer research UK 'race for life' next year. In the mean time tho, i'll keep running and talking to my dogs!


My two maniac dogs Molly and Tasha


References:
Roelands, B. Hasegawa, H. Watson, P. Piacentini, M.F. Buyse, L. De Schutter, G. Meeusen, R. The effects of acute dopamine reuptake inhibition on performance. Medicine and Science in Sport and Exercise (in press).

Maughan, R.J. Shirreffs, S.M. Watson, P. Exercise, heat, hydration and the brain. Journal of the American College of Nutrition 26; 604S-12S, 2007.

Meeusen, R. Watson, P. Hasegawa, H. Roelands, B. Piacentini, M.F. Central Fatigue - the serotonin hypothesis and beyond. Sports Medicine 36; 881-909, 2006.

1 comment:

  1. Ah, well I knew it was dopamine that left me feeling awesome after exercise, but I didn't know the rest - most insightful!

    ReplyDelete

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