Is it safe to trade off sleeping for excercise in order to get healthy? which is more important physical health (body) or mental sharpness (sleep)

Sleep: Its never wise to trade of sleep for exercise if you are getting 6 to 8 hours sleep, there is plenty of time to exercise.

Safe?: Don't exercise before sleep. If you wake up early as long as you don't get sleepy later in day or have problem functioning its ok.

Exercise can help: If your physician says you're healthy for regular exercise, it can help improve your energy, help regulate your sleep, and help you feel more rested and alert during the day. Make sure you don't exercise within 3 hrs of bed time. Keep a regular wake and sleep schedule even on weekends.

Not an either-or: Hi. You need both for physical and mental health: healthy sleep habits and regular exercise. Neither is more important. It's like asking, what's more important for human life - water, air, or food? No one right answer. You need them all. You need good sleep and regular exercise for optimal health.