Energy balance: a crucial issue for exercise and sports medicine

Validation of Polar Grit X Pro for Estimating Energy Expenditure during Military Field Training: A Pilot Study

Wearables are lightweight, portable technology devices that are traditionally used to monitor physical activity and workload as well as basic physiological parameters such as heart rate. However recent advances in monitors have enabled better algorithms for estimation of caloric expenditure from heart rate for use in weight loss as well as sport performance. can be used for estimating energy expenditure and nutritional demand. Recently, the military has adopted the use of personal wearables for utilization in field studies for ecological validity of training. With popularity of use, the need for validation of these devices for caloric estimates is needed to assist in work-rest cycles. Thus the purpose of this effort was to evaluate the Polar Grit X for energy expenditure (EE) for use in military training exercises. Polar Grit X Pro watches were worn by active-duty elite male operators (N = 16; age: 31.7 ± 5.0 years, height: 180.1 ± 6.2 cm, weight: 91.7 ± 9.4 kg). Metrics were measured against indirect calorimetry of a metabolic cart and heart rate via a Polar heart rate monitor chest strap while exercising on a treadmill. Participants each performed five 10-minute bouts of running at a self-selected speed and incline to maintain a heart rate within one of five heart rate zones, as ordered and defined by Polar. Polar Grit X Pro watch had a good to excellent interrater reliability to indirect calorimetry at estimating energy expenditure (ICC = 0.8, 95% CI = 0.61-0.89, F (74,17.3) = 11.76, p < 0.0001) and a fair to good interrater reliability in estimating macronutrient partitioning (ICC = 0.49, 95% CI = 0.3-0.65, F (74,74.54) = 2.98, p < 0.0001). There is a strong relationship between energy expenditure as estimated from the Polar Grit X Pro and measured through indirect calorimetry. The Polar Grit X Pro watch is a suitable tool for estimating energy expenditure in free-living participants in a field setting and at a range of exercise intensities.

Difference in Housing Temperature-Induced Energy Expenditure Elicits Sex-Specific Diet-Induced Metabolic Adaptations in Mice

OBJECTIVE

The aim of this study was to test whether increased energy expenditure (EE), independent of physical activity, reduces acute diet-induced weight gain through tighter coupling of energy intake to energy demand and enhanced metabolic adaptations.

METHODS

Indirect calorimetry and quantitative magnetic resonance imaging were used to assess energy metabolism and body composition during 7-day high-fat/high-sucrose (HFHS) feeding in male and female mice housed at divergent temperatures (20°C vs. 30°C).

RESULTS

As previously observed, 30°C housing resulted in lower total EE and energy intake compared with 20°C mice regardless of sex. Interestingly, housing temperature did not impact HFHS-induced weight gain in females, whereas 30°C male mice gained more weight than 20°C males. Energy intake coupling to EE during HFHS feeding was greater in 20°C versus 30°C housing, with females greater at both temperatures. Fat mass gain was greater in 30°C mice compared with 20°C mice, whereas females gained less fat mass than males. Strikingly, female 20°C mice gained considerably more fat-free mass than 30°C mice. Reduced fat mass gain was associated with greater metabolic flexibility to HFHS, whereas fat-free mass gain was associated with diet-induced adaptive thermogenesis.

CONCLUSIONS

These data reveal that EE and sex interact to impact energy homeostasis and metabolic adaptation to acute HFHS feeding, altering weight gain and body composition change.

Biomarkers Associated With Tumor Ki67 and Cathepsin L Gene Expression in Prostate Cancer Patients Participating in a Presurgical Weight Loss Trial

Our previous presurgical weight loss trial among 40 prostate cancer patients found that rapid (but not slow) weight loss resulted in increased tumor Ki67 and Cathepsin L (CTSL) gene expression. In follow-up analyses, we strove to better understand these unexpected findings. A correlative study was undertaken by performing additional analyses [free fatty acids (FFAs), plasma CTSL, and inflammatory cytokines] on remaining pre-post intervention sera and exploring associations with extant data on tumor Ki67, body composition, physical activity (PA), and fecal microbiota. Positive associations were observed between changes in % body fat and FFAs (ρ = 0.428, p = 0.026), insulin (ρ = 0.432, p = 0.019), and Interleukin-6 (ρ = 0.411, p = 0.041). Change in Ki67 was inversely associated with change in lean mass (ρ = -0.912, p = 0.001) and change in insulin (ρ = -0.650, p = 0.042). Change in insulin was also associated with CTSL (ρ = -0.643, p = 0.024) and FFAs (ρ = -0.700, p = 0.016). Relative abundance of Bifidobacterium was associated with CTSL (ρ = 0.627, p = 0.039) and FFAs (ρ = 0.691, p = 0.019); Firmicutes was positively associated with change in PA (ρ = 0.830, p = 0.003). Contrary to hypotheses, FFAs decreased with systemic fat loss. Moreover, although glucose metabolism improved, it was inversely associated with Ki67 and CTSL. Lean mass loss was highly correlated with increased Ki67. The relationships between prostate tumor Ki67 and CTSL and weight loss associated changes in FFAs, lean mass, and fecal microbiota warrant further investigation.

Does Eating Addiction Favor a More Varied Diet or Contribute to Obesity?-The Case of Polish Adults

The rapidly increasing prevalence of overweight and obesity indicates a need to search for their main causes. Addictive-like eating and associated eating patterns might result in overconsumption, leading to weight gain. The aim of the study was to identify the main determinants of food intake variety (FIV) within eating addiction (EA), other lifestyle components, and sociodemographic characteristics. The data for the study were collected from a sample of 898 Polish adults through a cross-sectional survey in 2019. The questionnaire used in the study included Food Intake Variety Questionnaire (FIVeQ), Eating Preoccupation Scale (EPS), and questions regarding lifestyle and sociodemographic factors. High eating addiction was found in more than half of the people with obesity (54.2%). In the study sample, physical activity at leisure time explained FIV in the greatest manner, followed by the EPS factor: eating to provide pleasure and mood improvement. In the group of people with obesity, the score for this EPS factor was the best predictor of FIV, in that a higher score was conducive to a greater variety of food intake. Sociodemographic characteristics differentiated FIV only within groups with normal body weight (age) and with overweight (education). In conclusion, food intake variety (FIV) was associated with physical activity at leisure time, and then with EPS factor “Eating to provide pleasure and mood improvement”, whereas sociodemographic characteristics were predictors of FIV only within groups identified by body mass index (BMI). Nevertheless, our observations regarding the eating to provide pleasure and mood improvement factor and its associations with food intake variety indicate a need for further research in this area. Future studies should also use other tools to explicitly explain this correlation.

OXYGEN CONSUMPTION AND ENERGY EXPENDITURE DURING AND AFTER STREET GAMES, ACTIVE VIDEO GAMES AND TV

ABSTRACT Introduction: Physical activity has become less frequent since the 1980s, even among more active children. Objective: To analyze excess post-exercise oxygen consumption (EPOC) and total energy expenditure (TEE) in children during and after three different activities. Methods: Sixteen healthy children (9.6±0.1 yrs.) randomly underwent the following procedures lasting 30 minutes on different days: (a) traditional games (PLAY), (b) active video game (Dance Dance Revolution; DDR), and (c) watching television (TV). Oxygen consumption (VO2) was measured at rest, at the 10th, 20th, and 30th minute of intervention, and for 40 minutes post-intervention. TEE was also measured. Results: At the end of intervention, VO2 had increased by 330% and 166% for PLAY and DDR, respectively, compared to the rest. EPOC in PLAY was seen to occur at the 10th, 20th, and 30th post-interventional minutes from 7.00±1.02 (at rest) to 10.83±0.94, 10.03±0.58, and 9.80±0.77mL.kg-1.min-1, respectively. However, EPOC in DDR occurred at only the 10th postinterventional minute (7.04 to 8.61 mL.kg-1.min-1; p<0.01). After intervention, TEE in PLAY was greater than in DDR and TV (112.08±19.45 vs 56.98±6.34 vs 36.39±4.5 kcal; p<0.01), respectively. Conclusions: PLAY induced children to reach a greater VO2 during activity and greater EPOC and TEE compared to DDR and TV. Level of evidence A1b; Crossover study.

Dynamic Energy Balance: An Integrated Framework for Discussing Diet and Physical Activity in Obesity Prevention-Is it More than Eating Less and Exercising More?

Understanding the dynamic nature of energy balance, and the interrelated and synergistic roles of diet and physical activity (PA) on body weight, will enable nutrition educators to be more effective in implementing obesity prevention education. Although most educators recognize that diet and PA are important for weight management, they may not fully understand their impact on energy flux and how diet alters energy expenditure and energy expenditure alters diet. Many nutrition educators have little training in exercise science; thus, they may not have the knowledge essential to understanding the benefits of PA for health or weight management beyond burning calories. This paper highlights the importance of advancing nutrition educators’ understanding about PA, and its synergistic role with diet, and the value of incorporating a dynamic energy balance approach into obesity-prevention programs. Five key points are highlighted: (1) the concept of dynamic vs. static energy balance; (2) the role of PA in weight management; (3) the role of PA in appetite regulation; (4) the concept of energy flux; and (5) the integration of dynamic energy balance into obesity prevention programs. The rationale for the importance of understanding the physiological relationship between PA and diet for effective obesity prevention programming is also reviewed.

Is there such a thing as sustainable physical activity?

There is a global need to diminish climate gas emissions, and a simultaneous call for enhanced levels of physical activity. Increased physical activity entails reduced risk for overweight and chronic diseases, as well as a potential to reduce transport's major contribution to global CO₂ emissions. However, increased physical activity level also implies increased energy expenditure. Therefore, we aim to introduce the concept of sustainable physical activity, and to suggest certain physical activity habits due to their potentially sustainable properties. Worldwide, a third of adults and four fifths of adolescents ought to be more physically active in order to comply with current physical activity recommendations. Yet, considering upcoming resource challenges, types of physical activity should be taken into account. Active transportation represents carbon-friendly means of transportation as well as an opportunity for enhanced physical activity. Physical activity conducted in the local community is likely to favor sustainability through less use of fossil fuel, as it makes transportation redundant. Moreover, going "back to basic", using less equipment and appliances for everyday tasks could contribute toward energy balance through increased physical activity, and could decrease resource use. Finally, balancing food intake and energy expenditure would require less food production with accompanying energy savings.