More days of either aerobic or strength exercise were associated with higher levels of albumin in men and women, except for men who participated in strength training exercise, where levels were lower. Albumin is important for transporting substances in the blood such as bilirubin, calcium, and progesterone, and for maintaining osmotic balance . Increased levels in active individuals may be an adaptation to exercise training to expand plasma volume . Albumin is associated with protein status in the body , where strenuous exercise increases albumin excretion  and low protein intake decreases rate of albumin synthesis . Men who strength train may thus have lower synthesis or higher excretion due to dietary intake  or reduced stimulus for albumin production.