A Ketone Monoester with Carbohydrate Improves Cognitive Measures Postexercise, but Not Performance in Trained Females

PURPOSE

The acute ingestion of a ketone monoester with the coingestion of a carbohydrate (KME + CHO) compared with carbohydrate (CHO) was investigated on cycling performance and cognitive performance in trained females.

METHODS

Using a two condition, placebo-controlled, double-blinded and crossover design, 12 trained females (mean ± SD: age, 23 ± 3 yr; height, 1.64 ± 0.08 m; mass, 65.2 ± 12.7 kg) completed a baseline assessment of cognitive performance (psychomotor vigilance testing (PVT), task switching, and incongruent flanker), followed by 6 × 5-min intervals at 40%, 45%, 50%, 55%, 60%, and 65% of their maximal power output (W max ) and then a 10-km time trial, concluding with the same assessments of cognitive performance. Participants consumed either 375 mg·kg -1 body mass of KME with a 6% CHO solution (1 g·min -1 of exercise) or CHO alone, across three boluses (50:25:25).

RESULTS

Blood β-hydroxybutyrate concentrations averaged 1.80 ± 0.07 and 0.13 ± 0.01 mM during exercise in KME + CHO and CHO, respectively. Blood glucose decreased after drink 1 of KME + CHO (~15%; P = 0.01) but not CHO, and lactate concentrations were lower in KME + CHO at 50%, 55%, 60%, and 65% W max (all P < 0.05) compared with CHO. Despite these changes, no differences were found between conditions for time trial finishing times (KME + CHO, 29.7 ± 5.7 min; CHO, 29.6 ± 5.7 min; P = 0.92). However, only KME + CHO resulted in increases in psychomotor vigilance testing speed (~4%; P = 0.01) and faster reaction times (~14%; P < 0.01), speed (~15%; P < 0.01), and correct responses (~13%; P = 0.03) in the incongruent flanker during posttesting compared with CHO.

CONCLUSIONS

The acute ingestion of a KME + CHO elevated blood β-hydroxybutyrate and lowered glucose and lactate across multiple time points during exercise compared with CHO. Although these changes did not affect physical performance, several markers of cognitive performance were improved by the addition of a KME in trained females.

A self-selected 16:8 time-restricted eating quasi-experimental intervention improves various markers of cardiovascular health in middle-age male cyclists

OBJECTIVES

Time-restricted eating (TRE) is a dietary intervention that may offer some protection against cardiovascular disease (CVD), while also preserving performance in athletes. To date however, research on TRE in an active population has only been conducted in college-age cohorts and the effects of TRE in an older, trained population are less understood. Therefore, the aim of this study was to compare the effects of a 4-wk, 16:8 TRE intervention on markers of CVD risk in middle-age, male cyclists.

METHODS

Participants (N = 12; age, 51.9 ± 8.6 y; training duration/wk, 375 ± 140 min; peak aerobic capacity, 41.8 ± 5.6 mL/kg/min) reported to the laboratory for two sessions (i.e., at baseline and post-TRE) where blood was drawn from an antecubital vein after an 8-h overnight fast. Dependent variables measured at baseline and post-TRE included insulin, cortisol, brain-derived neurotropic factor, free testosterone, thyroxine, triiodothyronine, C-reactive protein, advanced oxidative protein products, glutathione, tumor necrosis factor (TNF)-α, glucose, and a full lipid profile.

RESULTS

Compared with baseline, TRE significantly lowered TNF-α (12.3 ± 3.4 versus 9.2 ± 2.4 pg/mL; P = 0.02) and glucose concentrations (93.4 ± 9.7 versus 87.5 ± 7.9 mg/dL; P = 0.01), as well as significantly elevated high-density lipoprotein cholesterol levels (45.7 ± 13.7 versus 49.2 ± 12.3 mg/dL; P = 0.04), respectively. No further significant changes were observed between the remaining variables (all P > 0.05).

CONCLUSION

Overall, these data suggest that incorporating a 4-wk TRE intervention with habitual endurance training can significantly improve some markers of CVD risk and may compliment the robust health benefits derived from a regular exercise regimen.

A Self-Selected 16:8 Time-Restricted Eating Protocol Improves Fat Oxidation Rates, Markers of Cardiometabolic Health, and 10-km Cycling Performance in Middle-Age Male Cyclists

ABSTRACT

Witt, CR, Grozier, CD, Killen, LG, Renfroe, LG, O'Neal, EK, and Waldman, HS. A self-selected 16:8 time-restricted eating protocol improves fat oxidation rates, markers of cardiometabolic health, and 10-km cycling performance in middle-age male cyclists. J Strength Cond Res XX(X): 000-000, 2022-The purpose of this study was to assess the impact of 4 weeks, 16:8 time restricted eating (TRE) on markers of metabolic health and 10-km time trial (TT) performance in middle-age male cyclists. Subjects (n = 12; age, 40-60 years; V̇o2peak, 41.8 ± 5.6 ml·kg-1·min-1) consisting of individuals following a habitual Western diet completed a familiarization and 2 experimental trials [PRE] and [POST]. Following habitual Western diet without TRE, anthropometric measures were assessed, followed by completion of a graded exercise test and 10-km TT. Subjects then adhered to a 4-week TRE protocol where all calories had to be consumed within a self-selected 8-hour window and then returned for repeat testing. Although self-reported caloric intake did not statistically change PRE to POST, body mass (PRE, 83.2 ± 13.4 vs. POST, 80.7 ± 12.6 kg), fat mass (∼2.5 kg), and blood pressure (systolic, 8 mm Hg; diastolic, 4 mm Hg) were all significantly lower POST (all p < 0.05), with no changes in fat-free mass. Furthermore, fat oxidation significantly increased (PRE, 0.36 ± 0.03 vs. POST, 0.42 ± 0.03 g·min-1; p = 0.04) following the TRE intervention and 10-km TT performance improved by ∼2 minutes POST (PRE, 29.7 ± 7.3 vs. POST, 27.4 ± 5.5 minutes; p = 0.02). Overall, our data demonstrated that middle-age male cyclists adhering to a 4-week TRE protocol can improve their body composition profile and 10-km TT performance without detriments to fat-free mass.