The decrease of muscle glycogen may be useful for the improvement of endurance performance. Intense anaerobic exercise requires a high rate of glycogen utilization, but consecutive intense anaerobic exercises induce a pronounced decline of external power and muscle glycogen consumption. We hypothesized that a long rest period between consecutive intense anaerobic exercises may aid in sustaining external power and glycogen consumption. Secondly, we hypothesized that active rest (AR) during the long resting period may be more effective than passive rest (PR).Six subjects performed four 30-second Wingate tests (WAnT) with a 4-minute recovery between each bout (Consecutive method). The subjects also performed a similar exercise procedure, but with a 30-minute seated resting period after the second bout (PR method).The other six male subjects performed four 30-second WAnTs with a 4-minute recovery between each bout, with 30-minutes of cycling at 40% VO₂max after the second bout (AR method). The subjects also performed PR method.The total work during the third and fourth bouts was greatest under the AR condition, followed by the PR condition, and finally the Consecutive method (p<0.05 for all comparisons). Blood lactate concentration during resting period was significantly lower, while muscle glycogen consumption was greater AR method than PR method (p<0.05 for both).A long resting period between consecutive intense anaerobic exercises may prevent the decline in external power and work. Additionally, AR has more favorable effects on muscle glycogen consumption, resulting in very low muscle glycogen levels, even with a small total amount of exercise.

Recent studies indicate that exercise with a low muscle glycogen state enhances exercise-induced metabolic adaptation. However, it is unclear whether metabolic adaptation is involved with muscle glycogen depletion level. In this study, we investigated the effects of prior muscle glycogen depletion level on metabolic response during acute continuous exercise. Seven men completed two experimental trials consisting of two exercise sessions per day. During the first session, participants performed either intermittent exercise (IE) at VO₂max (the IE-CE trial) or continuous exercise (CE) at lactate threshold (the CE-CE trial). During the second session, participants performed 60 minutes of CE at lactate threshold. During this second session, fatty acid oxidation (FAO) was calculated. To determine muscle glycogen content and PGC-1α and PDK-4 mRNA abundance, muscle biopsies were taken at rest after the first session and 2 hours after the second session. After the first session, muscle glycogen content was significantly lower in the IE-CE trial (38.1±5.0 mmol/kg w.w.) than in the CE-CE trial (56.7±10.2 mmol/kg w.w.), P<0.05. FAO was higher in the IE-CE trial than the CE-CE trial at baseline and 15 minutes after the second session (both P<0.05). PGC-1α mRNA abundance increased after exercise (IE-CE, 5.9±2.5; CE-CE, 2.6±1.3-fold; P<0.1). PDK-4 mRNA abundance increased significantly after exercise (IE-CE, 22.2±8.8; CE-CE, 31.5±10.6-fold; P<0.05). PGC-1α and PDK-4 mRNA were not significantly different between the trials. In conclusion, continuous exercise with a slightly muscle glycogen-depleted state induced similar level of PGC-1α and PDK-4 mRNA expression, but attenuated FAO, compared to exercise with a moderate muscle glycogen-depleted state.

We conducted a 14−year follow−up study to analyze the hazard ratio(HR) of mortality regarding lifestyle−related factors in Saga Prefecture, Japan. The subjects included 2, 170 people, who were randomly selected from men and women aged from 40 to 69 years old, and who also completed the standardized questionnaire on lifestyle in 1983. Information about death and corresponding data were obtained either by mail and/or through the city offices in 1997. We found that a lower body weight, a lower physical fitness level, not consuming a balanced diet, and cigarette smoking to be significantly elevated risks for all−causes of death in males after adjustment by age and health status. In addition, these results did not change even after excluding subjects for early death. The HR of the female subjects who quit smoking was significantly high, although it changed to insignificant after excluding subjects for early death. These results suggested that being underweight might be an index of a positive risk of death, while maintaining a higher physical fitness level, being careful to consume a more balanced diet, and non smoking all appear to be indexes of a negative risk of death. In addition, these results might also be considered good evidence for improving poor health habits in health promotion activities.
Cessation of life ; Life Style ; Male population group ; Related ; Total

This study evaluates the pertinent cutoffs of Timed Up and Go (TUG) and Chair Stand (CS) tests for detecting cognitive impairment risk in Japanese elderly. Subjects were community-dwelling adults aged 65 or older (N = 455, 129 men and 326 women). Cognitive function was examined using Urakami’s test for Alzheimer’s disease; physical function was examined by TUG and CS. The maximum score for cognitive function was 15; impairment was defined as 12 or less. Receiver operating characteristic (ROC) analyses were performed to find an appropriate cutoff of TUG and CS for cognitive impairment. Furthermore, the sensitivity and specificity of the combined use of these measures independently distinguishing between subjects with and without a risk for cognitive impairment were determined. Fifty-four subjects (12%) scored as impaired on Urakami’s test. The optimal TUG cutoff for cognitive impairment was 6 seconds and 9 seconds for CS. The combined use of TUG and CS, based on a subject being positive on at least one measure, yielded sensitivity of 78% and specificity of 50%. Area under the ROC curve of TUG and CS were respectively 0.67 and 0.66. When divided into two groups according to the TUG cutoff value, the odds ratio of cognitive impairment in the slower group was 2.1 (95% confidence interval 1.25-3.37). For CS cutoff, the slower-group odds ratio was 3.57 (95% confidence interval 2.20-5.81). For TUG and CS combined, the slower-group odds ratio was 2.11 (95% confidence interval 1.03-4.34). TUG and CS are thus potent predictors for cognitive impairment among elderly adults.

High fat diet consumption induces fat accumulation in the liver. An understanding of when liver fat accumulation begins is important for exploring the mechanisms underlying fatty liver. The aim of this study was to investigate the processes of fat accumulation in the liver during high fat diet consumption with or without exercise using computed tomography (CT). Male 6 week old C57BL/6J mice were randomly assigned to the normal diet or high fat diet group. After 6 weeks, mice in the high-fat diet group were further divided into voluntary wheel exercise (HFD+Ex) and no exercise (HFD) groups. We measured body weight, food intake and locomotor activity in all mice. Liver fat accumulation was measured by CT scan weekly. Blood and tissue sampling was performed at the end of the experimental period. Following the 6 week exercise period, total body, mesenteric fat and liver weight in the HFD+Ex group were significantly lower than those in the HFD group. Alanine aminotransferase levels improved in HFD+Ex mice compared with those of HFD mice. The hounsfield unit value in HFD mice decreased between 3 and 8 weeks, suggesting that liver fat accumulation accelerated during this period. In contrast this decrease was not observed one week after exercise in HFD+Ex mice. These results suggest that liver fat accumulation estimated by CT was not observed until the 3rd week of high fat feeding while the effects of voluntary wheel exercise appeared immediately.

It is well known that decreased physical performance induces the decreased activity of daily living and increment of mortality rate in elderly subjects. On the other hand, a prolonged heart rate corrected-QT (QTc) interval is associated with an increased risk of cardiac sudden death and cardiac autonomic dysfunction. We investigated the associations between physical performance and QTc interval in elderly subjects. The subjects included 605 elderly persons (274 men and 331 women, age; 71.2±4.7 years) without a history of cardiovascular disease and taking cardioactive drugs. Resting 12-leads electrocardiography was measured after more than 5 minutes of rest. The QTc interval was calculated according to Bazett’s formula. The physical fitness test was performed to determine the physical performance (muscle strength, balance and walking abilities). The subjects were divided into four categories, which were defined as equally quantile distributions of QTc interval. The physical performance levels were significantly lower in the longest QTc interval group compared to the shortest QTc interval group in both men and women (p<0.05, respectively). Moreover, after adjusting for the age, the physical performance levels were significantly lower in the longest QTc interval group compared to the shortest QTc interval group, especially, this relationship was observed in late-stage elderly group (p<0.05, respectively). These results suggest that decreased physical performance levels were also associated with prolonged QTc interval in elderly subjects.

This study examined whether physical and cognitive function was independently associated with risk of Musculoskeletal Ambulation Disorder Symptom Complex (MADS) in community-dwelling older people. We examined 640 older people (315 men, 325 women; 65–89 years). We assessed physical performance by one-leg standing with eyes open, timed up and go (TUG), muscle strength, muscle power, and gait speed. Cognition was assessed using Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR), and Trail-Making Tests (TMT) A and B. We divided participants by physical function into “MADS” (one-leg standing < 15s or TUG ≥ 11s) and “non-MADS”, and identified cognitive impairment if MMSE was < 27 and CDR ≥ 0.5. We also grouped by sex and age (younger-old: 65–74 years and older-old: 75–89 years), and controlled for age, Body Mass Index, education and steps. Physical and cognitive function was significantly worse in the MADS groups. The younger-old men had poorer muscle strength, muscle power and TMT-A. The younger-old women had poorer muscle power, gait speed, MMSE and TMT-B. Older-old men had poorer muscle strength, and older-old women poorer gait speed (P < 0.05). The MADS groups also had significantly higher adjusted odds ratio (OR) for cognitive impairment (younger-old men: OR: 4.62; 95% confidence interval [CI]: 1.08–19.8; younger-old women: OR: 6.09; 95% CI: 1.03–35.9; P < 0.05). This study suggested that poorer physical and cognitive function was significantly associated with the risk of MADS, and these associations may be differ with sex and age.

This study aimed to examine characteristics of physical functions, physical activity, and cognitive functions among community-dwelling older people who stopped driving automobiles. Participants were 589 community-dwelling older people (age: 65–89, 71.4 ± 5.1 years; 403 men, 186 women). The participants underwent nine physical assessments—hand grip strength, knee extension strength, timed up-and-go test, chair stand, one leg standing with open eyes, functional reach, vertical jump, preferred gait speed, maximal gait speed—and were evaluated for physical activity; and five cognitive assessments—the Mini-Mental State Examination (MMSE), Logical Memory I and II (WMS-R LM-I, LM-II) subtests of the Wechsler Memory Scale-Revised; and Trail Making Test A and B (TMT-A, TMT-B). They were divided into current driver (379 men, 169 women) and driving cessation (24 men, 17 women) groups. Among men, the driving cessation group had poorer vertical jump, TMT-A, and TMT-B results, while women had poorer hand grip strength, one leg standing with open eyes, WMS-R LM-II, and LM-II results, and longer inactivity time, compared with the current driver group and adjusted for covariates (P < 0.05 for all). The findings suggest driving cessation among community-dwelling older people is significantly associated with poorer physical functions, physical activity, and cognitive functions compared with those in current drivers.