Wednesday, 25 February 2009
Body clock, nutrition and exercise
I watched Horizon documentary the other night:The Secret Life of Your Bodyclock and learned plenty about the way our bodies react throughout the day and night to our activities and conversely when those activities are best suited to our bodyclock. I was particularly interested by the ideas about exercise and eating. When is the best time to exercise and what should our eating patterns be like?
The documentary alluded to Siffre's famous experiments of living in a cave for 6 months without natural light to see how is body clock reacted. Based on this and other experts analysis the programme comes up with some interesting results:
- Between 7 and 11 in the morning our body has an increased blood pressure, vessels can't widen and blood is stickier (more resistance to flow) showing that the heart is under great pressure. Statistically you are three times more likely to have a heart attack.
(Something I already knew! Mornings are for larks, not for people....)
- If you increase your activity at the right time of day it can be beneficial! Exercise in the afternoon reduces blood pressure by 10 -11 % while exercise in the morning does not reduce bp at all.
Even gently walking in the afternoon can be beneficial.
- Body temp and alertness rises in afternoon and exercise is best late afternoon /early evening.
When training or the Olympics, the cyclist Chris Boardman says he found no pain in evening training like he experienced in the mornings. Records in cycling tend to be broken in afternoon and evening. In cycling hard training seems to be often conducted in the evenings when the body temperature has risen. This helps as the body seems to be in a pre-race or warm up mode.
(The only caveat was that balance and hand steadiness may be better in the morning.)
- Our eating patterns now show that the average UK main meal of the day is at 8pm. Linda Morgan from Univ Surrey says that over the last 100 years our eating patterns have changed: 100 years ago we had big breakfasts, large lunches and less in evening. Recently this has been reversed so that little of our day's calories are consumed in the morning and more later in the night. This means glucose remains in the blood more in the evening: high blood glucose levels in the evening is not great. According to her experiments into eating we should aspire to: "Eat breakfast like a king, lunch like a prince and dine like a pauper."
So we haven't learned something we didn't already know, right? I mean we train in the evening as that's when most lessons are held: after people have come home from school and work and not too late as to interfere with our sleeping (I find if I exercise late int he evening I have to wait some time to come down before I can go to bed).
Plus I eat too much anyway. Interestingly if I stack my calories up at the start of the day I'm in a better position for my insulin to regulate my blood glucose levels throughout the day (it seems). I did read a long time ago about an American football coach who recommended to players who wanted to lose weight to eat nothing after 8pm. This is something I aspire to do- it also helps with my IBS!