Physical Activity Behaviors and Physical Work Capacity in University Students during the COVID-19 Pandemic

Objective. The COVID-19 pandemic led to restricted access to sports and recreation facilities, resulting in a general decrease in physical activity. Many studies present the results of on-line questionnaires conducted during the pandemic, but there are few reports of objectively measured indicators of physical condition. Thus, the objective of this study was to assess the changes in physical work capacity, body composition, and physical activity behaviors in university students during 14 weeks of lockdown. Material and Methods. Twenty students of Tourism and Recreation (13 female and 7 male) participated in the study. The first examination was conducted in November 2020, and the second in March 2021. Body composition was assessed with a Tanita 418 MA device. The students performed the PWC 170 cycling test and completed the International Physical Activity Questionnaire (short version) on-line. Results. Neither physical work capacity nor body composition parameters changed substantially during the analyzed period. In the female students, vigorous physical activity decreased significantly, but no substantial changes occurred in weekly metabolic equivalent of task. In male students, walking days and metabolic equivalent of task decreased, but the changes were not significant. Conclusions. Fourteen weeks of COVID-19 lockdown had little effect on the body composition, physical work capacity level, and physical activity habits of Tourism and Recreation students. Studies with larger groups of participants should verify the current conclusions, and care should be taken when extrapolating to other populations.

Drivers of Pigeon Pea Consumption Among School-Aged Children in Central Tanzania

Background: Protein energy malnutrition (PEM) and iron deficiencies (ID) are of major public health concern in Tanzania including among school-aged children. PEM and ID in early childhood have serious, long-term consequences because they impede motor, sensory, social and emotional development, growth retardation, poor cognitive development, learning disability of children, lowered resistance to infectious diseases, and reduced physical work capacity. The objective of this study was to elucidate the drivers of pigeon pea consumption among school-aged children in Dodoma district, Central Tanzania. Understanding these drivers would be useful in promoting pigeon pea consumption among school-aged children as one of the strategies to increase dietary protein and iron intake.Methods: This study was a cross-sectional study in which data were collected using a questionnaire based on a combination of the Theory of Planned Behavior and Health Belief Model. The data were collected from caregivers (n = 138) in four villages in Kongwa district, Dodoma region, Central Tanzania. We used correlations and multiple regressions to assess associations between constructs and identify predictive constructs. Mann–Whitney U tests were used for score comparisons with a significant p-value set at <0.10.Results: Health value was significantly correlated with health behavior identity (rs = 0.63, p < 0.001) and also significantly predicted health behavior identity (rs = 0.49, p = 0.001). The constructs cues to action and control belief were significantly associated with intention (β = −0.41, p = 0.059 and β = 0.06, p = 0.019 respectively). Finally, we observed that intention was a significant predictor of behavior (β = 1.38, p = 0.001). We also observed a significant negative interaction between perceived barriers and intention to consume pigeon pea (β = −0.04, p = 0.006), indicating that perceived barriers limit intention to consume pigeon pea.Conclusion and Implication: Our findings indicate that when the caregiver places increased importance on preventing her school-aged child from being iron or protein deficient or indeed anemic (health value), it results in a positive evaluation of the effectiveness of giving pigeon pea to address these nutrient deficiencies. Programs and efforts aimed at promoting pigeon pea consumption should focus on educating caregivers on iron and protein deficiency and the role that pigeon pea could play in addressing these. However, perceived barriers such as pest infestation during storage need to be addressed to increase pigeon pea consumption. The involvement of post-harvest management specialists is therefore crucial. Along with this, increasing productivity and crop management is also crucial to ensure year-round affordable supply of pigeon pea.

Quantifying the impact of heat on human physical work capacity; part II: the observed interaction of air velocity with temperature, humidity, sweat rate, and clothing is not captured by most heat stress indices

Increasing air movement can alleviate or exacerbate occupational heat strain, but the impact is not well defined across a wide range of hot environments, with different clothing levels. Therefore, we combined a large empirical study with a physical model of human heat transfer to determine the climates where increased air movement (with electric fans) provides effective body cooling. The model allowed us to generate practical advice using a high-resolution matrix of temperature and humidity. The empirical study involved a total of 300 1-h work trials in a variety of environments (35, 40, 45, and 50 °C, with 20 up to 80% relative humidity) with and without simulated wind (3.5 vs 0.2 m∙s−1), and wearing either minimal clothing or a full body work coverall. Our data provides compelling evidence that the impact of fans is strongly determined by air temperature and humidity. When air temperature is ≥ 35 °C, fans are ineffective and potentially harmful when relative humidity is below 50%. Our simulated data also show the climates where high wind/fans are beneficial or harmful, considering heat acclimation, age, and wind speed. Using unified weather indices, the impact of air movement is well captured by the universal thermal climate index, but not by wet-bulb globe temperature and aspirated wet-bulb temperature. Overall, the data from this study can inform new guidance for major public and occupational health agencies, potentially maintaining health and productivity in a warming climate.

Quantifying the impact of heat on human physical work capacity; part III: the impact of solar radiation varies with air temperature, humidity, and clothing coverage

Heat stress decreases human physical work capacity (PWC), but the extent to which solar radiation (SOLAR) compounds this response is not well understood. This study empirically quantified how SOLAR impacts PWC in the heat, considering wide, but controlled, variations in air temperature, humidity, and clothing coverage. We also provide correction equations so PWC can be quantified outdoors using heat stress indices that do not ordinarily account for SOLAR (including the Heat Stress Index, Humidex, and Wet-Bulb Temperature). Fourteen young adult males (7 donning a work coverall, 7 with shorts and trainers) walked for 1 h at a fixed heart rate of 130 beats∙min−1, in seven combinations of air temperature (25 to 45°C) and relative humidity (20 or 80%), with and without SOLAR (800 W/m2 from solar lamps). Cumulative energy expenditure in the heat, relative to the work achieved in a cool reference condition, was used to determine PWC%. Skin temperature was the primary determinant of PWC in the heat. In dry climates with exposed skin (0.3 Clo), SOLAR caused PWC to decrease exponentially with rising air temperature, whereas work coveralls (0.9 Clo) negated this effect. In humid conditions, the SOLAR-induced reduction in PWC was consistent and linear across all levels of air temperature and clothing conditions. Wet-Bulb Globe Temperature and the Universal Thermal Climate Index represented SOLAR correctly and did not require a correction factor. For the Heat Stress Index, Humidex, and Wet-Bulb Temperature, correction factors are provided enabling forecasting of heat effects on work productivity.

The impact of heat on human physical work capacity; Part III: the impact of solar radiation varies with air temperature, humidity, and clothing coverage.

It is well-known that heat impacts human labour/physical work capacity (PWC), but systematic evaluations of solar radiation (SOLAR) effects and the interaction with air temperature and humidity levels and clothing are lacking, as most lab-studies are conducted in semi-nude subjects without radiation or only in a single climatic condition. Due to the high relevance of SOLAR in various occupations, this study quantified how SOLAR interacts with clothing and other primary environmental factors (air temperature/humidity) of importance to determine PWC in the heat. The data allowed the development of a SOLAR correction factor for predicting PWC in major outdoor industries. Fourteen young adult males (7 wearing a standardised work coverall (0.9 Clo), 7 with shorts and trainers (0.3 Clo) walked for 1-hour at a fixed heart rate of 130 b∙min-1, in seven combinations of air temperature (25 to 45 Celsius) and relative humidity (20 or 80%), with and without SOLAR (800 W/m2 from solar lamps). Cumulative energy expenditure in the heat, relative to the work achieved in a cool reference condition, was used to determine PWC%. Skin temperature was the primary determinant of PWC in the heat. In dry climates with exposed skin (0.3 Clo), SOLAR caused PWC to decrease exponentially with rising air temperature, whereas work coveralls (0.9 Clo) negated this effect. In humid conditions, the SOLAR-induced reduction in PWC was consistent and linear across all levels of air temperature, and clothing conditions. WBGT and UTCI based prediction equations of PWC represented SOLAR correctly. For heat indices not intrinsically accounting for SOLAR, correction factors are provided enabling forecasting of heat effects on work productivity.

An advanced empirical model for quantifying the impact of heat and climate change on human physical work capacity

Occupational heat stress directly hampers physical work capacity (PWC), with large economic consequences for industries and regions vulnerable to global warming. Accurately quantifying PWC is essential for forecasting impacts of different climate change scenarios, but the current state of knowledge is limited, leading to potential underestimations in mild heat, and overestimations in extreme heat. We therefore developed advanced empirical equations for PWC based on 338 work sessions in climatic chambers (low air movement, no solar radiation) spanning mild to extreme heat stress. Equations for PWC are available based on air temperature and humidity, for a suite of heat stress assessment metrics, and mean skin temperature. Our models are highly sensitive to mild heat and to our knowledge are the first to include empirical data across the full range of warm and hot environments possible with future climate change across the world. Using wet bulb globe temperature (WBGT) as an example, we noted 10% reductions in PWC at mild heat stress (WBGT = 18°C) and reductions of 78% in the most extreme conditions (WBGT = 40°C). Of the different heat stress indices available, the heat index was the best predictor of group level PWC (R2 = 0.96) but can only be applied in shaded conditions. The skin temperature, but not internal/core temperature, was a strong predictor of PWC (R2 = 0.88), thermal sensation (R2 = 0.84), and thermal comfort (R2 = 0.73). The models presented apply to occupational workloads and can be used in climate projection models to predict economic and social consequences of climate change.