Kiyoshi Shimaoka

Effects of home‐based combined resistance training and walking on metabolic profiles in elderly Japanese

Background:  To evaluate the effects of home‐based combined resistance training and walking on metabolic profiles in elderly Japanese subjects.

Effect of aging on the concentrations of nitrous oxide in exhaled air

Trace gases in exhaled air have been used as a simple means of assessing metabolic reactions. The investigations of trace gases derived from bacteria in human exhalation are usually hydrogen (H2) or methane (CH4). On the other hand, nitrous oxide (N2O) is also derived from microorganisms, especially denitrifying bacteria. Although many kinds of denitrifying bacteria have been isolated on and in the human body, there has been few concerning N2O. We studied 222 healthy people from the age of 5 to 85 years. The analysis of N2O in exhaled air was carried out by a infrared-photoacoustic (IR-PAS) analyzer. It was found that N2O ranged from 0 to 1670 ppbv in exhaled air and that 59% (131) of the subjects were producers of N2O. A highly significant relationship was observed between age and concentrations of N2O (r = 0.40, P < 0.01). The rate of production in young children and in the aged was significantly higher than that in adults aged 20-39 years (P < 0.01), and less than 30% were producers during puberty. The change of normal microflora on and in human body with aging may have caused the significant relationship between age and emissions of N2O.

Associations of intramyocellular lipid in vastus lateralis and biceps femoris with blood free fatty acid and muscle strength differ between young and elderly adults

The present study aimed to determine relationships between intramyocellular lipid and biochemical profiles or muscle strength in elderly (n = 15; mean age, 71 years) and young (n = 15; mean age, 21 years) male and female adults. Levels of intramyocellular lipid in the vastus lateralis and biceps femoris muscles were determined using 1H‐magnetic resonance spectroscopy. Fasting blood samples were collected to measure levels of glucose, insulin, haemoglobin A1c, total cholesterol, high‐density lipoprotein cholesterol, low‐density lipoprotein cholesterol, free fatty acid, triglyceride, adiponectin, and high‐sensitivity C‐reactive protein. Muscle strength was assessed as maximal voluntary contraction during isometric knee extension. Muscle cross‐sectional area in the vastus lateralis was measured using magnetic resonance imaging. Specific force (N cm−2) indicating force generation capacity was calculated as muscle strength (N) divided by the muscle cross‐sectional area of the vastus lateralis (cm2). The intramyocellular lipid content was similar in both muscles in both groups. The intramyocellular lipid content in the biceps femoris significantly correlated with serum free fatty acid levels (r = 0·62, P<0·05), and that in the vastus lateralis significantly and inversely correlated with specific force (r = −0·58, P<0·05) in the young, but not in the elderly adults. The relationship between the intramyocellular lipid content in the thigh muscles and biochemical profiles, or specific force differed between elderly and young adults. Age‐associated changes in morphology, function and metabolic factors apparently influence intramyocellular lipid metabolism in the thigh muscles.

Prolonged effectiveness of 12-month exercise-plus-diet intervention in Japanese adults at risk of impaired glucose or lipid metabolism

BACKGROUND AND OBJECTIVES To investigate the prolonged effects of a 12-month exercise-plus-diet intervention in Japanese adults at risk of impaired glucose or lipid metabolism. METHODS AND STUDY DESIGN A total of 180 participants were randomly divided into an intervention group (n=94), and a control group (n=86). An exercise-plus- diet intervention was conducted on the intervention group for 12 months. The effects were evaluated by questionnaire, physical examinations, and blood tests at baseline, 3 months, 12 months (the end of intervention), and 24 months (one year after the end of intervention). The control group took only the same examinations as the intervention group. RESULTS At the end of the 12-month intervention, body weight, waist circumference, fasting glucose, HbA1c, triglycerides, and LDL-cholesterol were improved in the intervention group compared to the control group (all p<0.05). One year after the end of the intervention, body weight, waist circumference, fasting glucose, triglycerides, and LDL-cholesterol were still decreased in the intervention group compared to the control group (all p<0.05), especially among non-overweight participants. Among overweight persons, only body weight in the intervention group was lower than the control group. The personal behaviours of physical activity and diet in the intervention group were also improved. CONCLUSIONS The 12-month exercise-plus-diet programs were found to be effective in improving glucose and lipid metabolism, as well as personal behaviour one year after completion of the intervention.