Other adverse physiological effects of microgravity Normal energy expenditure and risks of sex: – In healthy individuals Heart rate typically rises to around 130 beats/minute Systolic blood pressure typically rises to around 170 to 180 mmHg – In a stressful environment and with an unfamiliar (and particularly much younger) partner: Peak energy expenditure may rise to 5 to 6 METs or higher Heart rate and systolic blood pressure may rise significantly above usual maximums