After one night without sleep, average blood pressure rises by about 4 points and stays elevated for up to a day and a half in healthy men.

After staying awake for a day, healthy men in their early 30s with average weight experience a small but noticeable rise in blood pressure that stays elevated for up to a day and a half.

After 24 hours without sleep, heart rate drops slightly but then starts rising again over the next 8 hours, suggesting the body's response to sleep loss changes over time.

The heart's ability to pump blood per minute per body area remains stable even after 32 hours without sleep in healthy men.

Staying awake for up to a day and a half doesn't significantly affect the amount of blood the heart pumps with each beat in healthy men.

After one night without sleep, healthy men show changes in two blood chemicals related to blood vessel health, suggesting their blood vessels might not work as well.