When compared with the W40 , the W70 was associated with higher active energy expenditure ( 2.4 [ 0.6 ] and 3.1 [ 0.9 ] Kcal/min , respectively ; P < 0.0001 ) and a similar mean ( standard deviation ) oxygen uptake ( 5.5 [ 1 ] and 6.6 [ 1 ] ml/min per kilogram , respectively ; P = 0.07 ) .