I aim for seven hours of sleep every night but get more like six if I'm lucky. I'm getting to bed on time, but can't fall asleep as quickly as I used to. A recent poll revealed sixty percent of American adults experience insomnia a few nights a week. Unfortunately, they're not just suffering bad TV.

Studies show people who sleep less than six hours a night died earlier than those who got a full seven hours. My wife tells me to exercise more hoping it'll help. That's an interesting thought ' is there a connection between sleep and sweat?

Evidence does show exercise improves sleep, but new studies reveal not in the way we thought. In a study of women with insomnia, half the group was inactive while the other half did thirty minutes of moderate workout several times a week.

After four months, as expected, those in the active group slept forty-five minutes to an hour longer each night, woke less often and felt more energized. But the scientists were surprised to find in these women's journal entries no changes in sleep two months into the study.

It took a full four months for their sleep to improve - much longer than expected. Ironically, they also did not report sleeping better on the days they exercised. Instead, they noted a good night's sleep helped them exercise better the next day which suggests sleep may influence exercise more than the other way around.

It's possible people with sleep disorders have different brain wiring, that their stress system is hyper-aroused and require a prolonged exercise regime to overcome. But you can do something about your insomnia now. Improve your sleep by avoiding caffeine in the eight hours before bed and try to get to bed the same time every night.