You toss and turn, nod off, then wake up a few hours later. If this sounds familiar, take an evening walk instead of a sleeping pill. People who exercise for 50 minutes four to five hours before bedtime doze off 54 percent faster and stay asleep much longer, say researchers at the Federal University of São Paulo in Brazil. They speculate that exercise helps you feel more relaxed. And unlike medication, there aren’t any negative side effects to this prescription.