4.1.1. Optimizing Post-Exercise Recovery

Carbohydrates provide key substrates for the muscle and central nervous system during rest and exercise. It is still unclear if the recommended carbohydrate intake of 1.2 g/kg/h [190] is sufficient for this, or if a surplus could enhance post-exercise muscle glycogen resynthesis and whether female athletes or older individuals are affected differently. Until now, there is no evidence that post-exercise carbohydrate fuelling recommendations differ between ages and sexes. Thus, it is likely that carbohydrate loading strategies act in the same way in masters athletes, provided that they consume at least 8.0 g/kg body mass/day for daily fuel needs and recovery [190], additionally 30 to 70 g carbohydrates per hour of exercise—depending on exercise intensity and duration—for immune system recovery after intense exercise boots [191].

Proteins are essential nutrients for recovery from exercise. Post-exercise protein ingestion stimulates muscle protein synthesis (MPS), and the balance between synthesis and breakdown of muscle proteins determines recovery and adaptation to the exercise stimulus. Thus, sufficient provision of amino acids is critical to build muscle mass and strength with exercise training, as well as enhancing other adaptations [192]. In particular resistance exercise augments the ability of muscle to respond to protein intake. The optimal daily dietary protein intake depends on many factors, including age, sex, body size, habitual energy and nutrient intake as well as habitual exercise and PA. Moreover, acute dietary factors such as the quality of protein, defined by the spectrum of amino acids contained, the amount of protein ingested and the timing of protein ingestion and also the intake of

other nutrients can influence the response of muscle to protein intake [193]. It is clear that the essential amino acids are critical for optimal stimulation of MPS, but also as signals to stimulate the process. The essential amino acid leucine is of particular interest as it is a powerful signal for stimulation of the mammalian target of rapamycin (mTORC) 1 pathway, which is responsible for the initiation of protein translation and is thus often used as a proxy measure for MPS [194]. The recommended protein intake for professional athletes is between 20–25 g of high-quality protein consumed after exercise [195], preferably through the ingestion of whole foods [196], which are rich in dietary protein, vitamins, minerals, and other macronutrients (e.g., whole milk or eggs). Recent data sugges<sup>t</sup> that this amount may be suboptimal and insufficient for older people [197]. Thus, dietary protein recommendations for older adults should be increased (i.e., ≥30 g/meal or ≥1.2 g/kg body mass/day), which contain higher amounts of leucine (i.e., 78.5 mg/kg body mass/day) than current recommendations [198], and also considered on a meal-by-meal (every 3–4 h) basis [199,200]. Experts even suggested higher protein intakes for masters athletes (35–40 g/meal) to meet a daily target of ~1.5–1.6 g/kg body mass/day to optimize lean mass gains during resistance training [201]. Protein intakes in female masters athletes with energy intakes less than 1800 kcal/day are likely to be too low. To preserve lean tissue during periods of energy restriction, protein requirements are greater (i.e., 1.6–2.4 g/kg body mass/day) than during periods of energy balance [202]. Vegetarian athletes can increase the muscle anabolic potential by blending animal and plant protein sources [203], and vegan athletes should combine various plant-based proteins in a 50/50 ratio to provide a more balanced amino acid profile (e.g., maize/soybean, rice/soybean, rice/pea) or by fortifying plant-based proteins with leucine (3 g/meal) [204,205].
