Early chronotype with metabolic syndrome favours resting and exercise fat oxidation in relation to insulin‐stimulated non‐oxidative glucose disposal

Abstract

Early chronotypes (ECs) are often insulin-sensitive, in part, due to physical activity behaviour. It is unclear, however, if chronotypes differ in resting and/or exercise fuel oxidation in relation to insulin action. Using the Morningness-Eveningness Questionnaire (MEQ), adults with metabolic syndrome (ATP III criteria) were classified as EC (MEQ = 63.7 ± 0.9, n = 24 (19F), 54.2 ± 1.2 years) or late chronotype (LC; MEQ = 47.2 ± 1.4, n = 27 (23F), 55.3 ± 1.5 years). Carbohydrate (CHO) and fat oxidation (FOX, indirect calorimetry) were determined at rest, 55% and 85% VO 2 max , along with heart rate and rating of perceived exertion. Physical activity patterns (accelerometers), body composition (DXA) and insulin sensitivity (clamp, 40 mU/m 2 /min, 90 mg/dl) with an indirect calorimetry for non-oxidative glucose disposal (NOGD) were also determined. While demographics were similar, ECs had higher VO 2 max (P = 0.02), NOGD (P < 0.001) and resting FOX (P = 0.02) than LCs. Both groups increased CHO reliance during exercise at 55% and 85% VO 2 max (test effect, P < 0.01) from rest, although ECs used more fat (group effect, P < 0.01). ECs had lower sedentary behaviour and more physical activity during morning/midday (both, P < 0.05). FOX at 55% VO 2 max correlated with VO 2 max (r = 0.425, P = 0.004) whereas FOX at 85% VO 2 max related to NOGD (r = 0.392, P = 0.022). ECs with metabolic syndrome used more fat in relation to insulin-stimulated NOGD.

Intermediate versus morning chronotype has lower vascular insulin sensitivity in adults with obesity

“…Glucose regulation is established to rely on adequate capillary blood flow for nutrient exchange with myocytes. We previously reported that later chronotypes had lower GIRs than early chronotypes, which was paralleled with less carbohydrate oxidation as well as non‐oxidative glucose disposal 17,38 . Herein, while GIRs were not statistically significant, there was a medium effect size.…”

The diurnal pattern of moderate‐to‐vigorous physical activity and obesity: a cross‐sectional analysis

“…It is possible that the differences in BMI and WC cause the diurnal pattern of MVPA rather than the diurnal pattern causes changes of BMI and WC. Additionally, the biological clock may vary between individuals, which could lead to interindividual variability in responsiveness to physical activity [37]. Information regarding the chronotypes (i.e., morningness vs. eveningness) of study participants would have enhanced the validity of the study and the interpretation of the diurnal pattern of MVPA.…”

The effects of sleep disruption on metabolism, hunger, and satiety, and the influence of psychosocial stress and exercise: A narrative review

“…19 Interestingly, evidence also exists to suggest that the strength of the association between poor sleep quality and insulin resistance is dependent on chronotype, such that individuals with an evening chronotype may be at greatest risk. 20 Importantly, the evening chronotype has been linked to greater risk of depression and anxiety, 25 greater dietary energy density, 26 as well as reduced physical activity and lower cardiorespiratory fitness, 27 33 together indicating that sleep has effects specific to peripheral tissues that may contribute to or exacerbate metabolic disorders. 32 Finally, while all of the aforementioned studies have used multiple days (e.g., ≥4 days) of sleep restriction, the deleterious effects of short sleep on insulin sensitivity have been shown to begin after just 1 night of sleep restriction (4-h TIB) in healthy subjects.…”