Differential relationships between waist circumference and cardiorespiratory fitness among people with and without type 2 diabetes

Differential Age-Related Declines in Cardiorespiratory Fitness Between People With and Without Type 2 Diabetes Mellitus

Objective

To assess the extent to which the established age-related decline in cardiorespiratory fitness (CRF) is augmented in adult men with type 2 diabetes mellitus (T2DM).

Participants and Methods

This study used data from the Aerobics Center Longitudinal Study, conducted between September 18, 1974, and August 3, 2006, in primarily non-Hispanic white, middle-to-upper class adults. The analyses were restricted to adult men with complete data on age, CRF, and T2DM (35,307 participants). Quantile regression models were used to estimate age-related differences in CRF, estimated using a maximal treadmill test, between persons with and without T2DM. Smoking status and birth cohort served as covariates.

Results

Age-related declines in CRF were observed in men with and without T2DM. For men younger than 60 years, at low-mid percentiles of the CRF distribution the magnitude of the age-related decline in CRF was significantly higher (P-values=.00, .02) in men with T2DM than in those without T2DM. At upper percentiles, the decline with age between the 2 groups was virtually identical. Significant declines in CRF in men 45 years or younger were observed only at high levels of CRF for those without T2DM and at low levels of CRF for those with T2DM (P-values .00, .04).

Conclusion

This study reported that men younger than 60 years with T2DM at the low-mid CRF percentiles experience an accelerated age-related decline in CRF. Men younger than 60 years with T2DM exhibiting high levels of CRF experienced a decline in CRF comparable to men without T2DM. This study highlights the importance of incorporating sufficient levels of exercise or activity to maintain high CRF in men with T2DM.

Team Rehabilitation in Inflammatory Arthritis Benefits Functional Outcomes Along With Improved Body Composition Associated With Improved Cardiorespiratory Fitness

OBJECTIVE

We investigated the effect of team rehabilitation in inflammatory arthritis (IA) on body composition and physical function. Further, we examined whether body composition and physical function are associated with disability and cardiorespiratory fitness (CRF).

METHODS

The participants were 149 patients (74% women) with chronic arthritis, a mean age of 53 (SD 13) years, and mean disease duration of 21 (SD 13) years. They participated in a 4-week team rehabilitation program and were evaluated at prerehabilitation, and at 3 and 12 months postrehabilitation. Body composition was assessed by bioelectrical impedance analysis and CRF by the Åstrand 6-minute cycle test. ANCOVA with Bonferroni correction and linear mixed models were applied.

RESULTS

After 3 and 12 months, there were significant reductions in waist circumference and measures of fat, adjusted for age, sex, and baseline measures. The prevalence of adiposity and central obesity decreased after 12 months. Hand grip strength and timed sit-to-stand (TST) improved together with reduction in Health Assessment Questionnaire (HAQ) and increased VO₂max after 3 and 12 months. HAQ reduction over time was associated with prerehabilitation measures of lean mass of legs, hand grip strength, TST, and physical activity, and changes in hand grip strength, physical activity, and sedentary time, but not with changes of body composition. VO₂max improvement over time was associated with prerehabilitation BMI, waist circumference, measures of fat and lean mass, changes in BMI, waist circumference, and measures of fat.

CONCLUSION

In patients with IA, 4-week team rehabilitation benefited body composition, level of physical functioning, activity, and CRF for up to 12 months. Measures of physical function and activity were linked to HAQ over time, whereas body composition was linked to CRF.

Wand Stretching Exercise Decreases Abdominal Obesity Among Adults With High Body Mass Index Without Altering Fat Oxidation

Rationale

We designed a wand-based muscle stretching (WE) exercise program, which has become increasingly popular in physical therapy and has been used for elderly patients with adhesive capsulitis. However, studies regarding the effects of WE training on abdominal obesity and measures of cardiovascular risk factors among overweight/obese adults aged ≥55 years are rare.

Purpose

The objective of this study is to evaluate the effects of a 15-week wand stretching exercise program on waist circumference and cardiovascular risk factors in sedentary adults aged 55–70 years.

Methods

A total of 124 participants were randomly assigned to either participate in wand stretching exercise (WE) over a 15-week period or a control group (n = 62 each). Sixty participants in the WE group (26 overweight and 34 obese) and 51 in the control group (29 overweight and 22 obese) completed the study. The WE program included wand-assisted muscle stretching exercise on both the upper body and lower body for 40 min per day, 5 days per week, whereas the control group maintained their sedentary lifestyle.

Results

No significant improvements were observed in plasma glucose, insulin, and the homeostatic model assessment of insulin resistance (HOMA-IR) after exercise training. Compared with the control group, the WE group had more significant reductions in waist circumference among participants with a body mass index (BMI) < 25 kg/m² (−2.6 cm, 95% CI: −4.19 to −0.97 cm, d = 0.48) and BMI > 25 kg/m² (−2.5 cm, 95% CI: −4.1 to −0.9 cm, d = 0.59) (both P < 0.01). Furthermore, within groups, a significant increase in % fat free mass was observed after WE training. The basal metabolic rate was slightly increased, but the fat oxidation rate remained unaltered in the WE group. Improvements in low-density lipoprotein cholesterol to high-density lipoprotein cholesterol were minimal after WE. Significant reductions in high-sensitivity C-reactive protein were observed after WE only for participants with a BMI <25 kg/m².

Conclusion

The results suggest redistribution of a carbon source from the abdominal region to challenged skeletal muscle, following prolonged WE training. This abdominal fat reducing outcome of the WE is unlikely to be associated with fatty acid oxidation.