History of thermal and environmental physiology in Japan: the heritage of Yas Kuno.

Dr. Yas Kuno was a pioneer in the field of sweat gland physiology. He trained many research scientists who formed the first generation of thermal physiologists.

Comparison of single- or multifrequency bioelectrical impedance analysis and spectroscopy for assessment of appendicular skeletal muscle in the elderly.

Bioelectrical impedance analysis (BIA) is used to assess skeletal muscle mass, although its application in the elderly has not been fully established. Several BIA modalities are available: single-frequency BIA (SFBIA), multifrequency BIA (MFBIA), and bioelectrical impedance spectroscopy (BIS). The aim of this study was to examine the difference between SFBIA, MFBIA, and BIS for assessment of appendicular skeletal muscle strength in the elderly.

Association between lifestyle and physical activity level in the elderly: a study using doubly labeled water and simplified physical activity record.

Purpose: Physical activity level (PAL) is associated with all-cause mortality in the elderly. However, few studies have attempted to clarify the relationship between lifestyle and PAL in the elderly. This study aimed to examine the determinants of PAL in the elderly in terms of behavioral patterns and exercise intensity, and to validate the simplified physical activity record (sPAR).

Effect of prehydration on nasal mucociliary clearance in low relative humidity.

Objective: Nasal mucociliary clearance, which plays an important role in defending the respiratory system, tends to decrease under conditions of low relative humidity (RH). The purpose of this randomized cross-over study was to investigate the preventive effect of prehydration on nasal mucociliary clearance under low RH conditions.

Methods: Fourteen young healthy subjects were assigned to three interventions: prehydration (6ml/kg body weight) using water (W), prehydration using a carbohydrate-electrolyte beverage (CE), and control conditions (Cont) with no prehydration.

Extracellular water may mask actual muscle atrophy during aging.

Background: Skeletal muscle tissue holds a large volume of water partitioned into extracellular water (ECW) and intracellular water (ICW) fractions. As the ECW may not be related to muscle strength directly, we hypothesized that excluding ECW from muscle volume would strengthen the correlation with muscle strength.

Methods: A total of 119 healthy men aged 20-88 years old participated in this study.

Proximal electrode placement improves the estimation of body composition in obese and lean elderly during segmental bioelectrical impedance analysis.

Bioelectrical impedance analysis (BIA) is an affordable, non-invasive, easy-to-operate, and fast alternative method to assess body composition. However, BIA tends to overestimate the percent body fat (%BF) in lean elderly and underestimate %BF in obese elderly people. This study examined whether proximal electrode placement eliminates this problem.

Light-intensity activities are important for estimating physical activity energy expenditure using uniaxial and triaxial accelerometers.

This study evaluated the validity of the total energy expenditure (TEE) estimated using uniaxial (ACCuni) and triaxial (ACCtri) accelerometers in the elderly. Thirty-two healthy elderly (64-87 years) participated in this study. TEE was measured using the doubly labeled water (DLW) method (TEE(DLW)).

Genomic and non-genomic effects of aldosterone on the individual variation of the sweat Na+ concentration during exercise in trained athletes.

To clarify whether the resting background effects (genomic) or exercise-related action (non-genomic) of aldosterone (ALD) is primarily affected to an individual variation in the sweat Na+ concentration ([Na+]sweat), we analyzed the cross-sectional relationship between [Na+]sweat and the plasma ALD concentration during rest and exercise in a hot environment. Eleven college-aged male subjects with a mean maximal oxygen uptake of 48 (range 42-59) ml kg-1 min-1 performed three sessions of 20-min cycle exercise at two levels of intensity (40 or 60% VO2max) in a room maintained at 31 degrees C. The chest sweat rate (SRch) and its containing Na+ were higher and individual differences in SRch and [Na+]sweat were greater at 60% exercise than at 40% exercise.

Plasma volume and blood viscosity during 4 h sitting in a dry environment: effect of prehydration.

Background: Deep vein thrombosis and pulmonary thromboembolism are potential problems for travelers, including those who fly. We hypothesized that prehydration with an electrolyte-glucose beverage (EGB) would be better than water for maintaining body fluid balance and preventing increased blood viscosity in immobilized men.

Methods: There were 12 healthy men (24-38 yr) who participated in crossover trials of prehydration using EGB and H2O as well as a control condition (Con) with no prehydration.

The critical level of water deficit causing a decrease in human exercise performance: a practical field study.

To analyse the critical level of water deficit which causes a decrease in aerobic and anaerobic exercise performance, a step test score (STS) and 10 s maximal anaerobic power (MAP) output during cycling exercise were measured in two experiments (Ex-1, n=7, and Ex-2, n=9), before and after baseball practice, using subjects who played regularly. The measurements in both Ex-1 and Ex-2 were repeated under four conditions of fluid ingestion (FI) (FI of 80%, 60%, 40%, and 20% of the total sweat loss) on hot summer days. The subjects were allowed free access to a sports beverage, maintained at 10-15 degrees C, within any given FI condition during the exercise.