Association of cardiorespiratory fitness and adiposity with inflammatory biomarkers in young adults

Fit-Fat Index is better associated with heart rate variability compared to fitness and fatness alone as indicators of cardiometabolic human health

OBJECTIVES

Cardiorespiratory fitness and fatness indicators have been related to heart rate variability (HRV) parameters. The Fit-Fat Index (FFI) is a single index combining cardiorespiratory fitness and fatness indicators. To the best of our knowledge, no studies have previously analyzed whether FFI are related to cardiac autonomic nervous system activity assessed through HRV parameters. This study aimed (i) to examine the association of cardiorespiratory fitness, fatness indicators, and FFI with HRV parameters; and (ii) to report what of the different fatness indicators included in FFI is better associated with HRV parameters in sedentary adults.

METHODS

One hundred and fifty healthy adults (74 women; 76 men), aged between 18 and 65 years old, participated in this cross-sectional study. We measured cardiorespiratory fitness (maximal oxygen consumption) and fatness indicators (waist-to-height ratio [WHR], fat mass percentage [FM%] and visceral adipose tissue [VAT]). Three FFIs were calculated as the quotient between cardiorespiratory fitness and one out of three possible fatness indicators: Fit-Fat Index calculated waist-to-height ratio (FFIWHR ), Fit-Fat Index calculated with FM% (FFIFM% ), and Fit-Fat Index calculated with VAT (FFIVAT ). HRV parameters were measured in resting conditions using a Polar RS800CX.

RESULTS

FFIWTHR , FFIFM% and FFIVAT were related to different HRV parameters (β ranges between -0.507 and 0.529; R2 ranges between 0.096 and 0.275; all p < .001) and the association was stronger with HRV parameters than the isolated fitness or fatness indicators (β ranges between -0.483 and 0.518; R2 ranges between 0.071 and 0.263; all p < .001). FFIVAT was the index more consistently associated with HRV parameters (β ranges between -0.507 and 0.529; R2 ranges between 0.235 and 0.275; all p < .001).

CONCLUSION

Our study suggests that compound FFIs are better predictors of HRV parameters than either cardiorespiratory fitness or fatness indicators alone. The FFIVAT was the best index in terms of its association to HRV.

Physical Fitness Attenuates the Impact of Higher Body Mass and Adiposity on Inflammation in Women With Systemic Lupus Erythematosus

Aims

Higher body mass and adiposity represent independent contributors to the systemic low-grade inflammatory state often observed in patients with systemic lupus erythematosus (SLE). This study assessed the role of physical fitness in the association of body mass and adiposity with inflammation in women with SLE.

Methods

A total of 77 women with SLE were included in this cross-sectional study. We obtained body mass index, waist-to-height ratio, and body fat percentage as indicators of body mass and adiposity. Inflammation was assessed through Serum levels of C-reactive protein, interleukin 6, and leptin. Cardiorespiratory fitness was assessed with the 6-minute walk test, range of motion with the back-scratch test, and muscular strength with handgrip dynamometry.

Results

Cardiorespiratory fitness attenuated the association of both body mass index and body fat percentage with interleukin 6 (all, P<0.05). Range of motion attenuated the association of body mass index with interleukin 6 (P<0.05) and the association of body fat percentage with C-reactive protein (P<0.05). These interactions indicated that higher fitness was associated with a lower increase in inflammation per unit increase of body mass or adiposity. Muscular strength showed a non-significant trend to attenuate the association of body fat percentage with interleukin 6 (P=0.057) but potentiated the association of body fat percentage with leptin (P<0.05).

Conclusion

These findings suggest that higher levels of cardiorespiratory fitness and range of motion might attenuate the impact of higher body mass and adiposity on inflammation in women with SLE. The role of muscular strength requires further investigation.

Pathways linking activity, adiposity, and inflammation to bone mineral density in women and men from NHANES 2007 to 2010

OBJECTIVES

Age, sedentary activity, central adiposity, and inflammation have all been independently associated with bone mineral density (BMD). We assessed how the effects of sedentary activity and central adiposity on BMD of the lumbar spine and femoral neck change across early to late adulthood and whether these relationships are mediated by inflammation.

METHODS

We analyzed data from 7135 women and men 20 years of age and older from NHANES 2007 to 2010. Anthropometrics, sedentary activity (min/day), serum CRP (mg/dl), and BMD (gm/cm² measured by DXA scans) at the femoral neck and lumbar spine. Data were compared by age and sex groups and through causal mediation analysis.

RESULTS

The effect of waist circumference on BMD was significantly mediated by serum CRP at both skeletal sites in men and at the femoral neck in women. Sedentary activity did not have a direct relationship to BMD but was mediated by waist circumference in men. Least square means differed significantly by sex and age groups with a general age-related decline in BMD at both skeletal sites.

CONCLUSIONS

We found that central adiposity, independent of overall body size and composition as measured through BMI, has an inverse relationship with BMD that is mediated by serum CRP. In addition, the negative impact of increased sedentism acted through changes in central adiposity (waist circumference) but only in men. Although low bone density and osteoporosis are often considered degenerative diseases that primarily impact postmenopausal women, our findings show that sedentary activity and central adiposity impact bone density beginning in early adulthood in both women and men.

Combined Aerobic and Resistance Training Lowers Body Fat Percentage in Rural Black South African Women

Background: Obesity is currently one of the most dominating diseases affecting younger adults in South Africa. This is commonly caused by a poor lifestyle, which may lead to an increased risk of non-communicable diseases. Objectives: The aim of the study was to examine if a six-week concurrent resistance and aerobic training program could elicit body composition and cardiorespiratory changes in rural black college women. Methods: Forty sedentary black females (aged 18 - 25 years) were randomly assigned to a combined resistance and aerobic training (COM) group (n = 20) or a control group (n = 20). The COM group participated in four times weekly aerobic and resistance training. Aerobic training consisted of 30 minutes a session (week 1 - 3: cycling for 3 minutes at 60% heart rate reserve (HRR), followed by 2 minutes at 50% HRR; week 4 - 6: 3 minutes at 70% HRR, followed by 2 minutes at 60% HRR). Resistance training consisted of participants training at 50% of their one-repetition maximum (1-RM) for week 1 - 3, doing 3 sets of 15 repetitions; for week 4 - 6 at 60% 1-RM, doing 3 sets of 15 repetitions. Results: Following the intervention, the COM group significantly (P ≤ 0.05) decreased their body fat percentage when compared to the control group (P = 0.006; d = 0.9), while no significant changes were observed in waist-to-hip ratio (P = 0.223) and cardiorespiratory endurance (P = 0.260) in either group. Conclusions: Although body composition (especially waist circumference and body fat percentage) and cardiorespiratory fitness are recommended as the main targets of physical activity programs aimed at preventing CVD in college students, this study demonstrated that a six-week concurrent program improved body fat percentage, and not WHR and cardiorespiratory fitness, in sedentary rural college-aged females. Further, these findings suggest that one method of program design does not fit all populations and that exercise prescription should be targeted and not generalized.

Feasibility and concurrent validity of a cardiorespiratory fitness test based on the adaptation of the original 20 m shuttle run: The 20 m shuttle run with music

The purpose was to examine the feasibility of the 20m shuttle run test with music and to test its concurrent validity with the original 20m shuttle run test. A total of 386 adolescents (14.5±1.6 years old, 48.9% boys) participated in our study. A self-reported questionnaire was used to assess student's perception about the 20m shuttle run test with music and the original and to assess perceived exertion. Participants performed randomly the 20m shuttle run test with music and original two weeks apart. Average and maximum heart rate were monitored with heart rate monitors. The 20m shuttle run with music was a feasible test for measuring cardiorespiratory fitness in adolescents. The concurrent validity showed mean differences of 5.1±14.6 for shuttles, 0.3±0.8 km/h for speed, 0.5±4.1 for stages, and 1.5±4.1 for VO2max (all p<0.001) in favour of the 20m shuttle run with music vs. the original 20m shuttle run test. Mean difference for the rating of perceived exertion was 0.4±2.5 points (p=0.003). No significant difference was found between boys and girls. In conclusion, the 20mSRT-music is feasible and presents a good concurrent validity in adolescents, independently of the sex and it will be an alternative and good approach to assess cardiorespiratory fitness.

Cardiorespiratory fitness, adiposity, and ambulatory blood pressure in adolescents

BACKGROUND

This study examined the association of cardiorespiratory fitness (fitness) and adiposity (Body Mass Index [BMI] and waist circumference [WC]) with ambulatory blood pressure (ABP) and tested the moderating effect of adiposity on the association between fitness and ABP.

METHODS

A cross-sectional study was conducted with 370 adolescents aged 11-16 years. Fitness was assessed by a height-adjusted step test and estimated by heart rate recovery, defined as the difference between peak heart rate during exercise and heart rate two minutes postexercise. Adiposity was measured using dichotomized values for percentiles of BMI (≥85th) and WC (≥50th). ABP was measured every 30-60 minutes over 24 hours on a school day. Mixed-effects regression analysis was used.

RESULTS

Each unit increase in fitness was associated with a decrease of systolic blood pressure (SBP) [-0.058 mmHg, P=0.001] and diastolic blood pressure (DBP) [-0.043 mmHg, P<0.001] after adjustment for WC and covariates. Each unit increase in fitness was associated with a decrease in SBP [-0.058 mmHg, P=0.001] and DBP [-0.045 mmHg, P<0.001] after adjustment for BMI and covariates. Fitness and BMI≥85th percentile (or WC ≥ 50th percentile) interactions were not associated with ABP after adjustment for covariates.

CONCLUSIONS

Our findings indicate a small but statistically significant inverse effect of fitness on ABP in adolescents. No evidence of a modifying effect of adiposity on this association suggesting that fitness and weight management have essential roles for maintaining lower ABP in adolescents.

Cardiorespiratory Fitness Does Not Offset Adiposity-Related Systemic Inflammation in Physically Active Older Women

CONTEXT

Chronic inflammation increases diabetes risk and may be exacerbated by excess adipose tissue. Whether cardiovascular fitness can offset chronic inflammation associated with excess adipose tissue in older adults is unclear.

OBJECTIVE

The study aimed to examine the influence of cardiorespiratory fitness on links between adiposity and pro- and anti-inflammatory biomarkers related to metabolic risk in physically active older women.

DESIGN, SETTING AND PARTICIPANTS

Cross-sectional study comprising older community-dwelling women (n = 109; age, 65-70 yr).

MAIN OUTCOME

Cardiorespiratory fitness was assessed using a standardized submaximal test and participants were categorized into high and low adiposity-related metabolic risk (body mass index, waist-to-hip ratio (WHR) and total fat mass). The inflammatory biomarkers C-reactive protein (CRP), interleukin-6 (IL-6), IL-10, IL-18, adiponectin, monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein (MIP-1α) were analyzed.

RESULTS

Regardless of adiposity measure, women in the metabolic high-risk group had significantly (P<0.05) elevated CRP and lower adiponectin levels. Levels of IL-6 and MIP1-α were significantly elevated in the high-risk group defined by WHR and total fat mass. IL-18 level was significantly elevated in the high-risk group based on WHR only. Importantly, a high cardiorespiratory fitness level did not attenuate the detrimental links between adiposity measures and inflammation.

CONCLUSIONS

Altogether, cardiorespiratory fitness does not offset the detrimental links between adiposity and several inflammatory biomarkers related to metabolic risk in physically active older women. Reducing abdominal adipose tissue in older adults should be emphasized in efforts aiming to attenuate age-related systemic inflammation and metabolic risk regardless of cardiorespiratory fitness.