The Sex Effect
Compared with men, women have higher VLDL-TG clearance rates (which offset their higher rates of secretion of VLDL-TG from the liver) and maintain lower plasma TG concentrations. In women, as in men, a single prolonged bout of moderate-intensity endurance exercise (approximately 120 minutes of running at 60% of maximal oxygen uptake) reduces fasting plasma VLDL-TG concentrations by augmenting the clearance of VLDL-TG, whereas a shorter bout of exercise (60 minutes) at the same intensity has no effect (Figure 1). Therefore, men and women are equally sensitive to exercise in terms of duration and relative intensity, although absolute exercise energy expenditure is lower in women than in men (because women have lower body weight and absolute maximal oxygen uptake).
The same exercise bout has a much smaller effect on VLDL-TG clearance in women (a 20% increase above resting values) than in men (a 40% increase) and reduces the secretion of VLDL-TG from the liver in women but not in men. This sex-specific response to exercise is not entirely surprising, given that both the secretion and clearance rates of VLDL-TG are higher in women than in men at rest, leaving less room for VLDL-TG clearance to rise and more room for VLDL-TG secretion to fall in response to exercise.
Resistance Exercise
A single bout of whole-body isokinetic resistance exercise also leads to hypotriglyceridemia by augmenting VLDL-TG clearance. When matched for total energy expenditure (approximately 400 kcal), resistance exercise (eg, bench press, shoulder press, leg press, knee extension, rowing, hip flexion and extension, chin-ups) reduces plasma VLDL-TG concentration and increases the VLDL-TG plasma clearance rate by about 30% above resting values, whereas endurance exercise has no effect.
Therefore, it seems that resistance exercise is more potent, in that it requires a lower energy expenditure threshold than endurance exercise for eliciting changes in VLDL-TG metabolism leading to hypotriglyceridemia.