Masters athletes take longer to recover from high intensity exercise than training- matched younger athletes. Does increased protein intake enhance recovery?

Introduction: Masters athletes (MA) undertaking high intensity exercise recover muscular performance at rates similar to younger athletes (YA) following fatiguing, non–muscle damaging exercise such as cycling. However, following exercise–induced muscle damage from running, MA take longer than YA to recover. Older untrained adults exhibit age–related anabolic resistance to skeletal muscle repair and remodeling. We examined whether this anabolic resistance persists in MA and whether it contributes to slower rates of acute and chronic recovery of muscle performance compared to YA. Secondly, we examined whether increasing protein intake following high intensity exercise in MA can enhance the recovery of muscular performance.

Methods: Using doubly labelled water and muscle biopsy, study 1 compared muscle protein synthesis (MPS) rates of five masters triathletes (53 ± 2 yr, 55.7 ± 6.9 mL.kg-1.min-1) and six young (27 ± 2 yr, 62.3 ± 1.5 mL.kg-1.min-1) triathletes who completed a 30–min downhill run followed by three 20 km cycling time trials 10, 24 and 48 hr following the run. In study 2, eight masters triathletes (52 ± 2 yr, 51.8 ± 4.2 mL.kg-1.min-1) completed two exercise trials separated by seven days. Each trial consisted of morning strength testing and a 30–min downhill run followed by an 8 hr recovery period during which a moderate (0.3 g.kg-1) or high (0.6 g.kg-1) protein intake was consumed at regular intervals commencing immediately after the run. Strength, cycling time trial and perceptions of recovery were assessed pre– and post–exercise.

Results: The masters triathletes showed a significantly lower MPS rate compared to the younger triathletes (1.49 ± 0.12%.d-1 v 1.70 ± 0.09%.d-1). In comparison to baseline, there was a trend for masters triathletes to produce a slower cycle time trial (-3.0%) compared to younger triathletes (-1.4%) 10 hr post–run. In study 2, the higher protein intake did not improve recovery of cycling performance compared to the moderate protein intake. However, the higher protein intake showed a moderate beneficial effect in lowering the loss of afternoon strength (-3.6%) compared to the moderate protein intake (-8.6%). In addition, the high protein intake provided a large beneficial effect in reducing perceived fatigue over the 8 hr recovery period compared to the moderate protein intake.

Discussion: Taken together, it appears that regular training into older age does not offset age–related impairments in MPS. However, higher than recommended protein feedings may benefit recovery of subsequent performance in MA