Adrián Rodríguez-Castaño

INTRODUCTION: Although masks reduce pathogen spread during exercise, their physiological impact remains debated. PURPOSE: This study aimed to assess the physiological effect of wearing surgical and FFP2 masks on ventilatory function and perceived effort during a wide range of submaximal aerobic exercise intensities. METHODS: Twelve participants completed three randomized and counterbalanced trials: a) without mask; b) wearing surgical mask; c) wearing FFP2 mask. In each trial, participants performed an incremental intensity cycle ergometer test, consisting of 3-min stages ranging from 30% to 80% of maximal aerobic power. Ventilatory and metabolic variables were continuously measured using a breath-by-breath gas analyser. Heart rate was monitored via telemetry, blood lactate concentration obtained through fingertip samples, and perceived exertion recorded using the Borg 6–20 scale. Data were analysed using two-way repeated-measures ANOVA (mask × load), with Bonferroni post hoc tests applied when significant effects were detected (p<.050). RESULTS: Mask use significantly reduced ventilation, tidal volume, respiratory rate, VO2, VCO2, and end-tidal O2 pressure, while increasing end-tidal CO2 pressure and perceived exertion (p<.050). The surgical mask impaired these variables mainly at higher intensities (60–80% of maximal aerobic power; p<.050), whereas the FFP2 mask caused reductions across the full submaximal range in several ventilatory variables (p<.050), with consistently larger decreases than the surgical mask (0.17≤d≤0.69). Heart rate and blood lactate concentration were unaffected. CONCLUSION: Face masks during submaximal aerobic exercise impairs ventilatory function and increases perceived exertion, with greater effects from FFP2 than surgical masks. When required, surgical masks are preferable as they cause less respiratory restriction and discomfort.

Purpose : Although caffeine-induced increases in fat oxidation are well established under laboratory conditions, evidence during field-based exercise is limited. Therefore, this study aimed to examine the acute effects of 3 mg·kg ⁻¹ of caffeine on fat oxidation during a 1-hour field-based outdoor run performed at the individual intensity eliciting maximal fat oxidation (Fatmax). Methods : Fourteen healthy, endurance-trained runners (11 men, 3 women; = 58.6 [6.3] mL·kg ⁻¹ ·min ⁻¹ ) participated in a randomized, double-blind, placebo-controlled, crossover experiment. Participants completed 1 preexperimental trial to determine and Fatmax, followed by 2 experimental trials. During the experimental trials, participants ingested either caffeine (3 mg·kg ⁻¹ ) or a placebo 60 minutes before a 1-hour run at their individual Fatmax intensity covered on a 1.97-km outdoor running course. Substrate oxidation rates and energy expenditure were measured via indirect calorimetry using a portable gas analyzer and calculated through stoichiometric equations while heart rate was continuously monitored and ratings of perceived exertion were recorded using the Borg scale. Results : Caffeine significantly increased total fat oxidation during the 1-hour run (33.62 [9.23] vs 40.46 [11.32] g; P = .018; d = 0.76) and decreased carbohydrate oxidation (93.16 [37.84] vs 77.32 [30.35] g; P = .036; d = 0.66) compared with placebo, with no effect on total energy expenditure ( P = .936). Caffeine also reduced the rating of perceived exertion (9 [2] vs 8 [2]; P = .024; d = 0.75) with no effect on heart rate ( P = .140). Conclusion : Acute ingestion of 3 mg·kg ⁻¹ of caffeine enhances fat oxidation during 1 hour of running at Fatmax under field-based conditions, suggesting that caffeine may be an effective nutritional strategy to optimize fat utilization during real-world submaximal endurance exercise.

Purpose : This study aimed to investigate fat utilization during 1 hour of cycling at maximal fat oxidation and, secondarily, to assess menstrual symptoms across different phases of the menstrual cycle. Methods : Fifteen physically active, naturally menstruating women (age = 25 [4] y, ) completed a randomized crossover study involving 1 hour cycling at maximal fat oxidation intensity during 3 menstrual cycle phases: early follicular, peri-ovulatory, and midluteal. Phases were identified individually using mobile app tracking, urinary luteinizing hormone tests, and daily basal temperature and body mass recordings. During exercise, ventilatory variables were measured breath by breath with a gas analyzer to estimate fat and carbohydrate oxidation, and heart rate and the rating of perceived exertion (6–20 a.u., Borg scale) were recorded. Data was analyzed using linear mixed effects modeling. Results : There was no main effect of menstrual cycle phase on total fat oxidized ( P = .388), total carbohydrate oxidized ( P = .265), or total energy expended ( P = .839) during exercise. However, a higher mean heart rate was detected in the peri-ovulatory phase compared with the early follicular phase ( P = .004), and participants reported higher rating of perceived exertion in the midluteal phase compared with early follicular ( P = .003) and peri-ovulatory phases ( P = .024). Menstrual symptom scores were higher in early follicular phase compared with peri-ovulatory and midluteal phases ( P < .001). Conclusions : Fat oxidation during exercise at maximal fat oxidation intensity was not affected by the phase of the menstrual cycle in healthy, young, physically active, naturally menstruating women. However, variations in heart rate and perceived exertion suggest that physiological and perceptual responses to exercise may differ across phases.

Purpose: A cancer diagnosis is commonly associated with a decline in patient’s life satisfaction and more pessimistic expectations about the future. The identification of strategies to improve life satisfaction in patients with cancer is of great interest to health practitioners since it may be associated with a better prognosis of cancer and higher survival rates. Previous meta-analyses and reviews concluded that exercise could significantly improve health-related quality of life in this population, but the effects of exercise on life satisfaction are still not well-known. This review aims to analyse the effects of exercise programs on life satisfaction in people with cancer and individuals who have overcome cancer. Methods: The present systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. A thorough search of databases including Web of Science and PubMed/MEDLINE was carried out. Six studies (535 participants) in which the effect of an exercise program was compared to a non-exercise program control condition in patients with cancer were considered eligible. A subsequent meta-analysis was performed using the random effects model to calculate the standardized mean differences (SMD) and 95% confidence intervals (CI). Results: Exercise intervention improved satisfaction with life compared with a control condition (SMD = 1.28; p = 0.02 with a 95% CI of 0.22 to 2.34). Conclusion: Exercise could be considered an effective tool to improve life satisfaction in patients with cancer. Hence, professionals might consider the possibility of integrating physical exercise into strategies aimed at enhancing the low life satisfaction often experienced by patients. PROSPERO: CRD42023438146

The ergogenic effects of acute caffeine intake on endurance cycling performance lasting ~1 h have been well documented in controlled laboratory studies. However, the potential benefits of caffeine supplementation in cycling disciplines such as cross-country/mountain biking have been rarely studied. In cross-country cycling, performance is dependent on endurance capacity, which may be enhanced by caffeine, but also on the technical ability of the cyclist to overcome the obstacles of the course. So, it is possible that the potential benefits of caffeine are not translated to cross-country cycling. The main objective of this study was to investigate the effects of acute caffeine intake, in the form of coffee, on endurance performance during a cross-country cycling time trial. Eleven recreational cross-country cyclists (mean ± SD: age: 22 ± 3 years; nine males and two females) participated in a single-blinded, randomised, counterbalanced and crossover experiment. After familiarisation with the cross-country course, participants completed two identical experimental trials after the ingestion of: (a) 3.00 mg/kg of caffeine in the form of soluble coffee or (b) 0.04 mg/kg of caffeine in the form of decaffeinated soluble coffee as a placebo. Drinks were ingested 60 min before performing a 13.90 km cross-country time trial over a course with eight sectors of varying technical difficulty. The time to complete the trial and the mean and the maximum speed were measured through Global Positioning System (GPS) technology. Heart rate was obtained through a heart rate monitor. At the end of the time trial, participants indicated their perceived level of fatigue using the traditional Borg scale. In comparison to the placebo, caffeine intake in the form of coffee significantly reduced the time to complete the trial by 4.93 ± 4.39% (43.20 ± 7.35 vs. 41.17 ± 6.18 min; p = 0.011; effect size [ES] = 0.300). Caffeine intake reduced the time to complete four out of eight sectors with different categories of technical difficulty (p ≤ 0.010; ES = 0.386 to 0.701). Mean heart rate was higher with caffeine (169 ± 6 vs. 162 ± 13 bpm; p = 0.046; ES = 0.788) but the rating of perceived exertion at the end of the trial was similar with caffeinated coffee than with the placebo (16 ± 1 vs. 16 ± 2 a.u.; p = 0.676; ES = 0.061). In conclusion, the intake of 3 mg/kg of caffeine delivered via soluble coffee reduced the time to complete a cross-country cycling trial in recreational cyclists. These results suggest that caffeine ingested as coffee may be an ergogenic substance for cross-country cycling.

Pre-exercise intake of caffeine (from ~3 to 9 mg/kg) has been demonstrated as an effective supplementation strategy to increase fat oxidation during fasted exercise. However, a pre-exercise meal can alter the potential effect of caffeine on fat oxidation during exercise as caffeine modifies postprandial glycaemic and insulinemic responses. Hypothetically, the effect of caffeine on fat oxidation may be reduced or even withdrawn during fed-state exercise. The present systematic review aimed to meta-analyse investigations on the effect of acute caffeine intake on the rate of fat oxidation during submaximal aerobic exercise performed in the fed state (last meal < 5 h before exercise). A total of 18 crossover trials with randomised and placebo-controlled protocols and published between 1982 and 2021 were included, with a total of 228 participants (185 males and 43 females). Data were extracted to compare rates of fat oxidation during exercise with placebo and caffeine at the same exercise intensity, which reported 20 placebo–caffeine pairwise comparisons. A meta-analysis of the studies was performed, using the standardised mean difference (SMD) estimated from Hedges’ g, with 95% confidence intervals (CI). In comparison with the placebo, caffeine increased the rate of fat oxidation during fed-state exercise (number of comparisons (n) = 20; p = 0.020, SMD = 0.65, 95% CI = 0.20 to 1.20). Only studies with a dose < 6 mg/kg of caffeine (n = 13) increased the rate of fat oxidation during fed-state exercise (p = 0.004, SMD = 0.86, 95% CI = 0.27 to 1.45), while no such effect was observed in studies with doses ≥6 mg/kg (n = 7; p = 0.97, SMD = −0.03, 95% CI = −1.40 to 1.35). The effect of caffeine on fat oxidation during fed-state exercise was observed in active untrained individuals (n = 13; p < 0.001, SMD = 0.84, 95% CI = 0.39 to 1.30) but not in aerobically trained participants (n = 7; p = 0.27, SMD = 0.50, 95% CI = −0.39 to 1.39). Likewise, the effect of caffeine on fat oxidation was observed in caffeine-naïve participants (n = 9; p < 0.001, SMD = 0.82, 95% CI = 0.45 to 1.19) but not in caffeine consumers (n = 3; p = 0.54, SMD = 0.57, 95% CI = −1.23 to 2.37). In conclusion, acute caffeine intake in combination with a meal ingested within 5 h before the onset of exercise increased the rate of fat oxidation during submaximal aerobic exercise. The magnitude of the effect of caffeine on fat oxidation during fed-state exercise may be modulated by the dose of caffeine administered (higher with <6 mg/kg than with ≥6 mg/kg), participants’ aerobic fitness level (higher in active than in aerobically trained individuals), and habituation to caffeine (higher in caffeine-naïve than in caffeine consumers).