Primary Outcome Measures:
- Endocrine, metabolic, cardiovascular changes performance and autonomic nervous system activity before and after sleep restriction and after sleep recovery. [ Time Frame: Completion of 23 day study ] [ Designated as safety issue: No ]
Other: Sleep restriction and recovery
Overnight sleep recording, measures of endocrine and metabolic (from blood), cardiovascular (measures of blood pressure and heart rate), performance ( before and after sleep restriction and after sleep recovery.