Impact of ambient temperature on energy cost and economical speed during level walking in healthy young males

Study of the Vertical Structures, Thermal Comfort, Negative Air Ions, and Human Physiological Stress of Forest Walking Spaces in Summer

Forest walking is a popular, healthy, and light outdoor activity. The potential comprehensive relationships between the vertical structures, thermal comfort, negative air ions (NAI), and human physiological stress in forest walking spaces have not been determined. We performed an experiment in the Baishuihe National Nature Reserve, Sichuan Province, China. Thirty-two college students recruited as subjects completed a forest walk (approximately one kilometer) on the same trail divided into three vertical structure type subsections, namely: A (dense herb and shrub layers with a sparse tree layer), B (dense tree, herb and shrub layers), and C (dense tree and herb layers with a sparse shrub layer). When the subjects passed preset environmental measurement points, staff measured climatic indexes (air temperature, relative humidity, wind velocity, surface temperature and global radiation) and NAI levels, and these data were input into the Rayman model to form a comprehensive thermal comfort index, the physiologically equivalent temperature (PET). PET and NAI differences and dynamic data among the subsections were analyzed. The subjects’ brain waves, heart rates (HRs), and walking speed (S) were digitally recorded. We selected brain wave θ, γ and β-high/α rates, neuroemotional indexes (stress and relaxation) and HR as physiological indicators, and S as an auxiliary indicator. The correlations between PET and NAI with physiological and auxiliary indexes were analyzed. Forest type C showed the lowest PETs and highest NAIs along with the most stable dynamic changes. PET was negatively correlated with HR and positively correlated with γ (12 channels). NAI was positively correlated with S and relaxation and negatively correlated with γ (two channels) and the β-high/α ratio (five channels). These comprehensive relationships suggest that dense tree, sparse shrub, and high-coverage herb layers combined with optimal temporal conditions (before noon or after a light rain) form the best thermal comfort and NAI conditions conducive to reducing human physiological pressures during summer daytime forest walking. These results provide theoretical references for forest walking and spatial regulation.

Intra-day variation in daily outdoor walking speed among community-dwelling older adults

Background

Walking speed is an important measure associated with health outcomes in older individuals, such as dependency and death. This study aimed to examine whether the walking speed of community-dwelling older adults varies between time periods within a day, as measured outdoors in daily life. We aimed to determine the types of walking speed variations and examine the factors associated with them.

Methods

Daily life outdoor walking speed was measured in 92 participants (average age 71.9 years±5.64) using a GPS smartphone app for 1 month. Average walking speeds for five time periods were analyzed with a linear mixed model. Intra-day walking speed variation patterns were classified by latent class analysis. Factors associated with the class were identified by logistic regression analysis.

Results

A statistically significant difference in average walking speed was found between early morning (1.33 m/s), and afternoon (1.27 m/s) and evening (1.26 m/s) (p < 0.01). The intra-day variation in walking speed was attributed to variation in cadence. Two classes were identified: (1) fast walking speed with large variation and (2) slow walking speed with little variation; hypertension and frailty level were associated with the class.

Conclusion

The results suggest that there is intra-day variation in walking speed in daily life, wherein the speed is the fastest early in the morning and slower in the afternoon and evening. A larger variation in the walking speed was related to the health status without hypertension or frailty. These results suggest that if a person shows less intra-day variation in walking speed, this could be a sign that they are susceptible to hypertension and an increased frailty level.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-021-02349-w.

Reference value on daily living walking parameters among Japanese adults

Aim

Walking speed is closely related to numerous health outcomes. It has typically been measured in laboratory settings, where individuals can intentionally change their walking speed. It can be accurately measured in daily life using a smartphone global positioning system. We aimed to present a reference value on walking speed in daily life by sex and age.

Methods

The data were obtained using a walking monitoring service involving global positioning system technology. A secondary data analysis was carried out. Four daily living walking parameters – daily living walking speed, daily living walking cycle, daily living step length and daily living cadence – of 8429 Japanese persons were measured in their daily life using a smartphone application.

Results

The means (standard deviations) of daily living walking speed, daily living walking cycle, daily living step length and daily living cadence were 1.30 m/s (0.10 m/s), 1.02 s (0.06 s), 65.55 cm (5.38 cm) and 118.86 steps/min (6.76 steps/min), respectively. Notably, daily living walking speed in those aged >65 years was significantly slower than in those aged <65 years.

Conclusions

The present reference values and age differences of daily living walking parameters can be used to compare daily living walking speed data measured by other devices, such as accelerometers. This could allow for a consensus on the definition of daily walking speed that can be utilized for assessing health outcomes among older individuals. Geriatr Gerontol Int 2020; 20: 664–669.