Effects of a brisk walk on lipoprotein lipase activity and plasma triglyceride concentrations in the fasted and postprandial states

Abstract

This study aimed to determine whether changes in plasma heparin-releasable lipoprotein lipase (LPL) activity following a brisk walk were associated with decreases in fasting and/or postprandial triglyceride (TG) concentrations. Two groups of pre-menopausal women participated. In one group (fasting study group, n=10), TG concentrations and post-heparin plasma LPL activity were measured in the fasted state on two occasions: approximately 18 h after a 2-h treadmill walk at 50% maximal oxygen uptake (exercise trial); and after a day of no exercise (control trial). The other group (postprandial study group, n=9) undertook two oral fat tolerance tests (blood samples taken fasting and for 6 h after a high-fat meal), with plasma LPL activity measured 6 h after meal ingestion. Pre-conditions were the same as for the fasting study group (i.e. control and prior exercise). Prior exercise reduced fasting TG concentrations by 23 (7)% (fasting study group) [mean (SEM)] and by 18 (9)% (postprandial study group) (both P<0.05), and the postprandial TG response by 23 (6)% (postprandial study group) (P<0.01). Plasma LPL activity was not significantly increased by exercise in either the fasting or postprandial study groups. However, exercise-induced changes in both fasting and postprandial LPL activity were significantly correlated with the respective exercise-induced changes in fasting TG concentration and the postprandial TG response (r=-0.70 and -0.77 respectively, P<0.05 for both). These data suggest that increased LPL activity may contribute to the hypotriglyceridaemic effect of moderate exercise, although other mechanisms are also likely to be involved.

Exercising for Metabolic Control: Is Timing Important?

“…In the setting of high-fat meals, the results have constantly been in favor of exercise and, as previously mentioned, if exercise sessions were to take place with sufficient time prior to a meal, their lipid-lowering effects would be more evident [32,35,36,39,40,42,54,59,60], with no significant difference between continuous and accumulated bouts [48]. Such results cannot be completely transferred to the generally recommended mixed, moderate-fat meals an adult is to consume in order to preserve health [61].…”

“…In fact, changes in muscle LPL activity and plasmatic LPL concentration appear to be well correlated to changes in triglyceridemia, which makes this enzyme a plausible, yet partial, explanation for the TG-lowering effect of exercise. [40,42]. Considering that exercise-induced LPL activation does not occur until 4 h postexercise and lasts for 18–24 h after an exercise session [55,56,57], LPL can certainly not be responsible for changes in TG levels outside this time frame.…”

“…The remaining 18 studies investigated the effect of exercise on postprandial events, modulating some parameters related to meals and exercise (i.e. exercise intensity and duration, meal size and composition) [36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53]. …”

“…Interestingly, in healthy individuals, exercising in the fasted state rules strongly in favor of TG control [32,35,36,39,40,42,54,59,60], leaving glycemia basically unaltered [33,64,65,66,67,68]. On the other hand, regularly training in this state prevents weight gain and lipid-induced insulin resistance in people consuming hypercaloric and high-fat diets [34].…”

Effect of prior exercise on postprandial lipemia and markers of inflammation and endothelial activation in normal weight and overweight adolescent boys

“…One possibility is that TG are cleared faster from the circulation following acute exercise mediated by an increase in the activity of skeletal muscle lipoprotein lipase (LPL), which has been shown to occur in a time course consistent with the postprandial reduction of TG (Seip et al 1997;Zhang et al 1998). However, exerciseinduced reductions in PPL have also been documented in the absence of changes in LPL activity (Gill et al 2003b;Katsanos et al 2004). The exercise-induced attenuation of postprandial TG may also be mediated by a reduction in hepatic TG synthesis and VLDL-TG secretion (Gill and Hardman 2003).…”