The purpose of this double-blinded, crossover randomized and counterbalanced study was to compare the effects of ingesting a tepid commercially available carbohydrate-mentholcontaining sports drink (menthol) and an isocaloric carbohydrate-containing sports drink (placebo) on thermal perception and cycling endurance capacity "in a simulated home virtual cycling environment". It was hypothesized that the addition of menthol would improve indicators of thermal perception and improve endurance exercise capacity. Twelve healthy, endurance-trained males (age 29 ± 5 years, height 181 ± 6 cm, body mass 79 ± 2 kg and V ̇O2 max 57.3 ± 6.4 mL kg −1 min −1 ) completed two experimental trials on a stationary bicycle without external air flow. Each trial consisted of (1) cycling for 60 min at 90% of the first ventilatory threshold while receiving a fixed amount of menthol or placebo every 10 min followed immediately by (2) cycling until volitional exhaustion (TTE) at 105% of the intensity corresponding to the respiratory compensation point. TTE did not differ between both conditions (541 ± 177 and 566 ± 150 s for menthol and placebo; p > 0.05) and neither did ratings of perceived thermal comfort or thermal sensation (p > 0.05). Also, the rectal temperature at the end of TTE was comparable between menthol and placebo trials (38.7 ± 0.2°C and 38.7 ± 0.3°C, respectively; p > 0.05). The present results demonstrate that the addition of menthol to commercially available sports drink does not improve thermal comfort or endurance exercise capacity during ∼65 min of intense virtual cycling.

Serious amateur and elite athletes regularly take part in structured physiological testing sessions so that their progress gets tracked and training loads in the training plan correctly prescribed. Commonly, athletes are tested for the maximal oxygen uptake (V̇O2max) and maximal lactate steady state intensity (MLSS). While for the former expensive laboratory equipment is required, the latter requires multiple exercise trials for accurate determination. INSCYD athletic performance software is designed to enable continuous monitoring of these two parameters throughout the season after undertaking a single visit exercise testing session involving blood lactate sampling and power output measurement. The purpose of the present study was to assess validity of the software by its estimates of V̇O2max and MLSS and compare them to gold standard laboratory measures. 11 trained participants (V̇O2max 61.0 ± 7.9 mL ∙ kg-1 ∙ min-1) took part in this study consisting of formal graded V̇O2max test, multiple MLSS trials and a recommended test to obtain the data later fed the INSCYD athletic performance software. Both V̇O2max relative (∆=0.13 ml.kg-1.min-1, p=0.885) and MLSS calculated values (∆=2 W, p=0.655) were within expected daily variation and thus the estimations considered valid. It can be concluded that INSCYD athletic performance software offers its users utility to accurately predict V̇O2max and MLSS provided that the practitioner has a good idea of where the MLSS lies. However, caution is required when interpreting other parameter estimates provided by the software due their questionable scientific validity.

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 (V̇O2peak 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.

It was previously demonstrated that postexercise ingestion of fructose–glucose mixtures can lead to superior liver and equal muscle glycogen synthesis as compared with glucose-based carbohydrates (CHOs) only. After an overnight fast, liver glycogen stores are reduced, and based on this we hypothesized that addition of fructose to a glucose-based breakfast would lead to improved subsequent endurance exercise capacity. In this double-blind cross-over randomized study (eight males, peak oxygen uptake: 62.2 ± 5.4 ml·kg−1·min−1), participants completed two experimental trials consisting of two exercise bouts. In the afternoon of Day 1, they completed a cycling interval training session to normalize glycogen stores after which a standardized high-CHO diet was provided for 4 hr. On Day 2, in the morning, participants received 2 g/kg of CHOs in the form of glucose and rice or fructose and rice, both in a CHO ratio of 1:2. Two hours later they commenced cycling exercise session at the intensity of the first ventilatory threshold until task failure. Exercise capacity was higher in fructose and rice (137.0 ± 22.7 min) as compared with glucose and rice (130.06 ± 19.87 min; p = .046). Blood glucose and blood lactate did not differ between the trials (p > .05) and neither did CHO and fat oxidation rates (p > .05). However, due to the duration of exercise, total CHO oxidation was higher in fructose and rice (326 ± 60 g vs. 298 ± 61 g, p = .009). Present data demonstrate that addition of fructose to a glucose-based CHO source at breakfast improves endurance exercise capacity. Further studies are required to determine the mechanisms and optimal dose and ratio.