Goroh Okano

Age-Related Changes in Intramyocellular Lipid in Humans by in vivo 1H-MR Spectroscopy

Background: It is considered that the increasing intramyocellular lipid (IMCL) affects health risks and muscle attenuation. Though body fat increases significantly with age in lean humans, it is not known whether IMCL increases or not. In this study, we investigated the changes with age in IMCL concentrations in skeletal muscles using 1H-MR spectroscopy and studied them in relation to body fat percentage, waist-hip ratio, and blood components. Methods: Twenty-four lean young (age 21.2 ± 1.9, BMI 21.5 ± 1.8) and 23 lean old (age 70.9 ± 2.4, BMI 21.7 ± 1.3) subjects took part in the study. Subjects were grouped by gender into age- and BMI-matched young and old groups. The 1H-MRS was obtained from the tibialis anterior (TA), medial gastrocnemius (MG) and soleus (SOL) muscles. Results: The IMCL content in SOL and MG in the old was found to be higher (p < 0.01) than that in the young. No age difference in IMCL content in TA was found. IMCL concentrations in SOL were higher than those in MG and TA in the order of SOL > MG > TA (p < 0.01). IMCL content correlated significantly with waist-hip ratio in all skeletal muscles. A significant relationship was observed between percent body fat and IMCL in TA and MG (p < 0.05). However, no correlation was found between IMCL content in each muscle and BMI. The IMCL content in all skeletal muscles significantly correlated with HbA1c, triglyceride, total cholesterol and LDL cholesterol concentrations. Conclusion: These results suggest that increased IMCL in both lean older men and women might be related to body composition, blood lipids and lipoprotein profiles, and that this might affect muscle attenuation.

Leisure Time Physical Activity as a Determinant of Self-Perceived Health and Fitness in Middle-Aged Male Employees

Leisure Time Physical Activity as a Determinant of Self‐Perceived Health and Fitness in Middle‐Aged Male Employees: Goroh Okano, et al. Division of Exercise Science, School of Medicine, Sapporo Medical University—Self‐perceived health and fitness are epidemiological predictors of subsequent mortality and/or functional limitation. The present study was designed to analyze which lifestyle factors contribute to good status of self‐perceived health and fitness in middle‐aged male employees. Participants (n=401) aged 50–59 were assessed as to the status of self‐perceived health and fitness, and various lifestyle factors including nutrition, smoking, drinking, physical activity, psychological stress, sleeping and relaxation. Logistic regression analysis revealed that among the lifestyle factors surveyed in the present study, doing exercise/sports at a medium level (either ≥4.5METs/1–2 times per week or <4.5METs/≥3–4 times per week) of physical activity index (PAI) was the only predictor of good self‐perceived health. Similarly, doing exercise/sports at or above the medium level of PAI was identified as the only independent predictor of good self‐perceived fitness. In addition, maintaining the habit of doing exercise/sports at or above the medium level of PAI throughout the year, and having this habit through the 4 th and 5th decades of life or starting to have it from the age of 50 through 59 were important to obtain a good status of self‐perceived health and fitness. These findings suggest that leisure time physical activity level is a determinant of good health and fitness in the middle‐aged male employees in the present study.

Effect of pre-exercise fructose ingestion on endurance performance in fed men

Twelve trained males, in a fed state, were studied to examine the effect of pre-exercise fructose ingestion on endurance capacity during prolonged cycling exercise. Sixty minutes prior to exercise, subjects ingested either 60 or 85 g fructose or a sweet placebo. Mean exercise intensity initially required 62% of the maximal aerobic power and thereafter increased to elicit 72 and 81% of maximal aerobic power at 90 and 120 min of exercise, respectively. Exercise time (mean +/- SE) to exhaustion was significantly increased after fructose ingestion, as compared to placebo ingestion (145 +/- 4 vs 132 +/- 3 min, P less than 0.01). During the exercise, no differences were observed between both trials for oxygen uptake, heart rate, or perceived exertion. Serum glucose and insulin levels between both trials were not significantly different throughout the experiment. There were also no significant differences in serum-free fatty acids and glycerol levels as well as respiratory exchange ratio between fructose and placebo trials during the exercise. The results suggest that fructose ingestion is of benefit before prolonged exercise, because it provides a carbohydrate source to contracting muscles without transient hypoglycemia and a depression of fat utilization, and thereby delays the fatigue.

Effect of elevated blood FFA levels on endurance performance after a single fat meal ingestion.

PURPOSE This study was designed to examine the effect of elevated blood free fatty acid (FFA) levels on carbohydrate (CHO) oxidation and cycling performance after ingesting a single fat meal (FM). METHODS Four hours before cycling exercise, nine trained males consumed either a FM (4711 kJ; 30% CHO, 61% fat, and 9% protein) or control meal (CM) (4877 kJ; 58% CHO, 31% fat, and 11% protein). The intensity of exercise employed was 67% of the maximal oxygen consumption (VO2max) for the first 120 min of exercise, followed by an increase to 78% VO2max. RESULTS The FM ingestion significantly (P < 0.05 and P < 0.01) elevated serum FFA levels above those resulting from CM ingestion almost throughout the entire exercise. A significantly (P < 0.05 and P < 0.01) lower respiratory exchange ratio in the FM versus the CM trials was observed during the first hour of exercise. This was accompanied by a significantly greater amount of fat oxidized at 20 (P < 0.01) and 60 min (P < 0.05) of FM trials and a significantly smaller amount of CHO oxidized at 20 min (P < 0.05) of FM trials. However, endurance time and work production did not differ between the FM (141 +/- 8 min, 134333 +/- 6049 kg x m (SEM)) and CM (138 +/- 5 min, 131450 +/- 4737 kg x m) trials. Also, there were no significant differences in oxygen consumption, heart rate, and perceived exertion or in glucose, lactate, and triglyceride levels in the blood. CONCLUSIONS These results suggest that the elevated blood FFA levels after a single FM ingestion reduce CHO oxidation early in exercise, but this decrease in CHO oxidation would not be adequate enough to contribute to an increased endurance.