TABLE 2

LPL studies indicate that the underlying cellular events during inactivity (NEAT deficiency) are distinct from the cellular events after exercise training

Inactivity mechanismsExercise mechanisms
Comparison studied for LPLInactivity (not standing) vs. normal spontaneous intermittent standing/ambulation during nonexercise physical activityExercise vs. normal nonexercise physical activity (spontaneous intermittent standing/ambulation)
Fiber type mostly affectedRed oxidative muscle fibers have ≥10-fold lower LPL activity during inactivityWhite glycolytic muscle fibers have 2.5-fold greater LPL activity after exercise
LPL mRNA involvementNo difference in LPL mRNA between inactive and controlLPL mRNA expression increases 2.5-fold in multiple glycolytic muscles after exercise
Evidence of inhibitory pathwayTranscription of an inhibitory gene suppresses LPL by a posttranslational mechanismNo evidence for inhibitory gene
  • The mechanisms regulating LPL during physical inactivity (“Inactivity mechanisms” column) and during exercise training (“Exercise mechanisms” column) were studied in comparison with the same referent control group (i.e., normal Sprague-Dawley rats with only intermittent and spontaneous nonexercise physical activity). Table is redrawn from refs. 1,2,85.