Monitoring core body temperature (T_c) during training and competitions, especially in a hot environment, can help enhance an athlete’s performance, as well as lower the risk for heat stroke. Accordingly, a noninvasive sensor that allows reliable monitoring of T_c would be highly beneficial in this context. One such novel non-invasive sensor was recently introduced onto the market (CORE, greenTEG, Rümlang, Switzerland), but, to our knowledge, a validation study of this device has not yet been reported. Therefore, the purpose of this study was to evaluate the validity and reliability of the CORE sensor. In Study I, 12 males were subjected to a low-to-moderate heat load by performing, on two separate occasions several days apart, two identical 60-min bouts of steady-state cycling in the laboratory at 19 °C and 30% relative humidity. In Study II, 13 males were subjected to moderate-to-high heat load by performing 90 min of cycling in the laboratory at 31 °C and 39% relative humidity. In both cases the core body temperatures indicated by the CORE sensor were compared to the corresponding values obtained using a rectal sensor (T_rec). The first major finding was that the reliability of the CORE sensor is acceptable, since the mean bias between the two identical trials of exercise (0.02 °C) was not statistically significant. However, under both levels of heat load, the body temperature indicated by the CORE sensor did not agree well with T_rec, with approximately 50% of all paired measurements differing by more than the predefined threshold for validity of ≤0.3 °C. In conclusion, the results obtained do not support the manufacturer’s claim that the CORE sensor provides a valid measure of core body temperature.

Post-exercise recovery strategies influence the body’s ability to restore physiological homeostasis, replenish energy stores, repair muscle damage, and promote desired adaptations, which improve exercise performance. This narrative review examines the impact of nutritional strategies commonly used for enhancing recovery and subsequent exercise performance, particularly when athletes face short recovery periods. Carbohydrate ingestion is essential for glycogen replenishment, especially within the initial hours post-exercise, with its impact dependent on the types, timing, and amount. Protein is essential for accelerating muscle recovery and achieving a positive nitrogen balance, depending on the type and dosage. The co-ingestion of carbohydrates with proteins or fats is explored for its role in maximizing glycogen resynthesis and muscle repair, with evidence supporting the addition of protein to suboptimal carbohydrate intake for enhanced recovery. Moreover, this review addresses the potential benefits of creatine and caffeine co-ingestion for accelerating glycogen synthesis and improving subsequent performance. Hydration strategies, including the use of milk-based beverages and electrolyte solutions, are also discussed, emphasizing their importance in maintaining fluid balance and optimizing recovery. This review also highlights the emerging role of micronutrients such as omega-3 fatty acids, antioxidants, and sodium bicarbonate in reducing muscle damage and improving acid–base balance. Evidence supports the tailored use of these nutritional strategies, particularly for athletes managing tight competition/training schedules. Future research should focus on refining individualized approaches for recovery and investigating the impact of novel supplements on subsequent performance.

Purpose: This study aimed to investigate whether carbohydrate ingestion during 3 h long endurance exercise in highly trained cyclists at a rate of 120 g h⁻¹ in 0.8:1 ratio between fructose and glucose-based carbohydrates would result in higher exogenous and lower endogenous carbohydrate oxidation rates as compared to ingestion of 90 g h⁻¹ in 1:2 ratio, which is the currently recommended approach for exercise of this duration. Methods: Eleven male participants (V̇O_2peak 62.6 ± 7 mL kg⁻¹ min⁻¹, gas exchange threshold (GET) 270 ± 17 W and Respiratory compensation point 328 ± 32 W) completed the study involving 4 experimental visits consisting of 3 h cycling commencing after an overnight fast at an intensity equivalent to 95% GET. During the trials they received carbohydrates at an average rate of 120 or 90 g h⁻¹ in 0.8:1 or 1:2 fructose-maltodextrin ratio, respectively. Carbohydrates were naturally high or low in ¹³C stable isotopes enabling subsequent calculations of exogenous and endogenous carbohydrate oxidation rates. Results: Exogenous carbohydrate oxidation rates were higher in the 120 g h⁻¹ condition (120–180 min: 1.51 ± 0.22 g min⁻¹) as compared to the 90 g h⁻¹ condition (1.29 ± 0.16 g min⁻¹; p = 0.026). Endogenous carbohydrate oxidation rates did not differ between conditions (2.15 ± 0.30 and 2.20 ± 0.33 g min⁻¹ for 120 and 90 g h⁻¹ conditions, respectively; p = 0.786). Conclusions: The results suggest that carbohydrate ingestion at 120 g h⁻¹ in 0.8:1 fructose-maltodextrin ratio as compared with 90 g h⁻¹ in 1:2 ratio offers higher exogenous carbohydrate oxidation rates but no additional sparing of endogenous carbohydrates. Further studies should investigate potential performance effects of such carbohydrate ingestion strategies.

Restoring skeletal muscle and hepatic glycogen content during short-term (<6 h) recovery from prolonged exercise is pertinent for athletes seeking to maximize performance in repeated exercise bouts. Previous research suggests co-ingestion of fructose-glucose carbohydrate sources augments hepatic and has equivalent effects on skeletal muscle glycogen storage during short-term recovery from prolonged exercise compared to isocaloric glucose ingestion. The aim of the present investigation was to determine if this has a discernible effect on subsequent exercise capacity. Eight trained endurance runners and triathletes performed two experimental trials in a single-blind, randomised, and counterbalanced cross-over design. Trials involved treadmill running to exhaustion at 70 %V[Combining Dot Above]O2max, a four-hour recovery with 90 g.h-1 of glucose-maltodextrin (GLU+MAL) or fructose-maltodextrin (FRU+MAL) ingestion (1:1.5 ratio), and a second bout of treadmill running to exhaustion at 70 %V[Combining Dot Above]O2max. Exercise capacity in bout two was significantly greater with FRU+MAL (81.4 ± 22.3 vs. 61.4 ± 9.6 min, P = 0.02), a large magnitude effect (ES = 1.84 ± 1.12, 32.4 ± 19.9 %). Total carbohydrate oxidation rates were not significantly different during bout one or two between-trials, although total carbohydrate oxidized in bout two was significantly greater with FRU+MAL (223 ± 66 vs. 157 ± 26 g, P = 0.02). Ingested carbohydrate oxidation rates were greater during bout two with FRU+MAL (P = 0.001). Plasma glucose and non-esterified fatty acid concentrations were not significantly different between-trials. Plasma lactate concentrations were significantly greater during recovery prior to bout two with FRU+MAL (P = 0.001). Self-reported nausea and stomach fullness during bout two were marginally in favour of FRU+MAL. Short-term recovery of endurance capacity was significantly enhanced with FRU+MAL vs. GLU+MAL ingestion during recovery.

Purpose: Ingesting readily oxidized carbohydrates (CHO) such as sucrose during exercise can improve endurance performance. Whether lactose can be utilized as a fuel source during exercise is unknown. The purpose of this study was to investigate the metabolic response to lactose ingestion during exercise, compared with sucrose or water. Methods: Eleven participants (age, 22 ± 4 yr; V̇O_2peak, 50.9 ± 4.7 mL·min⁻¹·kg⁻¹) cycled at 50% W _max for 150 min on five occasions. Participants ingested CHO beverages (lactose or sucrose; 48 g·h⁻¹, 0.8 g·min⁻¹) or water throughout exercise. Total substrate and exogenous CHO oxidation was estimated using indirect calorimetry and stable isotope techniques (naturally high ¹³C-abundance CHO ingestion). Naturally low ¹³C-abundance CHO trials were conducted to correct background shifts in breath ¹³CO₂ production. Venous blood samples were taken to determine plasma glucose, lactate, and nonesterified fatty acid concentrations. Results: Mean exogenous CHO oxidation rates were comparable with lactose (0.56 ± 0.19 g·min⁻¹) and sucrose (0.61 ± 0.10 g·min⁻¹; P = 0.49) ingestion. Endogenous CHO oxidation contributed less to energy expenditure in lactose (38% ± 14%) versus water (50% ± 11%, P = 0.01) and sucrose (50% ± 7%, P ≤ 0.05). Fat oxidation was higher in lactose (42% ± 8%) than in sucrose (28% ± 6%; P ≤ 0.01); CHO conditions were lower than water (50% ± 11%; P ≤ 0.05). Plasma glucose was higher in lactose and sucrose than in water (P ≤ 0.01); plasma lactate was higher in sucrose than in water (P ≤ 0.01); plasma nonesterified fatty acids were higher in water than in sucrose (P ≤ 0.01). Conclusions: Lactose and sucrose exhibited similar exogenous CHO oxidation rates during exercise at moderate ingestion rates. Compared with sucrose ingestion, lactose resulted in higher fat and lower endogenous CHO oxidation.