Effects of using high-intensity interval training and calorie restriction in different orders on metabolic syndrome: A randomized controlled trial

Exercise training impacts skeletal muscle remodelling induced by metabolic syndrome in ZSF1 rats through metabolism regulation

Metabolic syndrome (MetS), characterized by a set of conditions that include obesity, hypertension, and dyslipidemia, is associated with increased cardiovascular risk. Exercise training (EX) has been reported to improve MetS management, although the underlying metabolic adaptations that drive its benefits remain poorly understood. This work aims to characterize the molecular changes induced by EX in skeletal muscle in MetS, focusing on gastrocnemius metabolic remodelling. ¹H NMR metabolomics and molecular assays were employed to assess the metabolic profile of skeletal muscle tissue from lean male ZSF1 rats (CTL), obese sedentary male ZSF1 rats (MetS-SED), and obese male ZF1 rats submitted to 4 weeks of treadmill EX (5 days/week, 60 min/day, 15 m/min) (MetS-EX). EX did not counteract the significant increase of body weight and circulating lipid profile, but had an anti-inflammatory effect and improved exercise capacity. The decreased gastrocnemius mass observed in MetS was paralleled with glycogen degradation into small glucose oligosaccharides, with the release of glucose-1-phosphate, and an increase in glucose-6-phosphate and glucose levels. Moreover, sedentary MetS animals' muscle exhibited lower AMPK expression levels and higher amino acids' metabolism such as glutamine and glutamate, compared to lean animals. In contrast, the EX group showed changes suggesting an increase in fatty acid oxidation and oxidative phosphorylation. Additionally, EX mitigated MetS-induced fiber atrophy and fibrosis in the gastrocnemius muscle. EX had a positive effect on gastrocnemius metabolism by enhancing oxidative metabolism and, consequently, reducing susceptibility to fatigue. These findings reinforce the importance of prescribing EX programs to patients with MetS.

Estimation methods to detect changes in cardiorespiratory fitness due to exercise training and subsequent detraining

PURPOSE

To determine whether estimated maximal oxygen consumption ([Formula: see text]) can detect cardiorespiratory fitness (CRF) changes by behavioral modifications. This study compared changes in measured [Formula: see text]O_2max (m[Formula: see text]O_2max) through exercise intervention with e[Formula: see text]O_2max using a multiple regression model (MRM) and linear extrapolation method (LEM).

METHODS

A cross-sectional analysis involving 173 adults was conducted to establish an MRM by including age, sex, body mass index, questionnaire score, heart rate (HR) from step test, and m[Formula: see text]O_2max. Subsequently, 15 men participated in an intervention experiment comprising an 8-week, high-intensity interval training, followed by 8-week detraining, and completed anthropometric measurements, questionnaires, step tests, and m[Formula: see text]O_2max tests. m[Formula: see text]O_2max changes throughout the intervention were compared to e[Formula: see text]O_2max changes calculated using the MRM and LEM. The LEM used the HR during the step test with constant values (predetermined [Formula: see text]O₂), such as the Chester step test.

RESULTS

Inclusion of the step test HR in a questionnaire-based MRM improved the estimation power, although the MRM underestimated higher m[Formula: see text]O_2max values. In the intervention, m[Formula: see text]O_2max increased by 20.0 ± 14.1% (P < 0.01) and subsequently decreased by 9.5 ± 6.6% (P < 0.01) after exercise training and detraining, respectively. Significant method × time interactions were observed between m[Formula: see text]O_2max and e[Formula: see text]O_2max in the MRM but not in the LEM, i.e., an apparent systematic error (underestimation of high values) of the MRM was absent in the LEM, although the correlation between m[Formula: see text]O_2max and e[Formula: see text]O_2max using the LEM was moderate.

CONCLUSION

e[Formula: see text]O_2max, particularly using the MRM with HR as an explanatory factor, is not an appropriate method for detecting CRF changes along with behavioral modifications.

CLINICAL TRIAL REGISTRATION

Registered number, UMIN000041031; Registered date, 2020/07/08; URL, https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000046855.

Socioeconomic status relates to exercise habits and cardiorespiratory fitness among workers in the Tokyo area

OBJECTIVES

This survey aims to investigate consciousness regarding habitual exercise among workers in urban areas and to analyze the associations of workers' socioeconomic status with their habitual exercise and cardiorespiratory fitness (CRF).

METHODS

Ten thousand participants, who worked in the Tokyo area of Japan, were recruited for the questionnaire-based survey. The questionnaire elicited participant's characteristics, socioeconomic status (eg, employment status and annual income), habitual exercise status, and consciousness regarding exercising. After the data-cleaning procedure, 9406 participants were selected for analyses. CRF was estimated by a validated equation model.

RESULTS

Some (32.9%) participants had an exercise habit, and 93% recognized that exercise is good for health. Of the nonexercise habit group (n = 6308), 73% wanted to develop an exercise habit, and "spare time (40%)" and "financial capability (16%)" were the two most necessary conditions for habituating exercise. As socioeconomic statuses increased, the odds ratios (ORs) for engaging in habitual exercise increased among full-time (1.22) versus part-time (reference) employees and those having high (1.76) versus low (reference) incomes, whereas the ORs for low CRF risk decreased among full-time (0.78) versus part-time (reference) employees and those having high (0.53) versus low (reference) incomes.

CONCLUSIONS

Although most workers recognized the benefits of exercise, many were unable to develop exercise habits and believed that they could develop exercise habits if they had the time and financial capabilities. The survey suggests that workers with a higher socioeconomic status more likely to obtain favorable physical fitness, indicating a health disparity among workers in urban areas.