Physical and autonomic functionality in women with breast cancer pre and post chemotherapy: a case control study.

BACKGROUND: Breast cancer (BC) is one of the most incident types of cancer among women in the world. Although chemotherapy is an effective way to treat several types of cancer, it may also cause serious complications, including cardiotoxicity. This study aimed to identify the impact of chemotherapy on functional capacity, muscle strength and autonomic function. METHODS: Ten breast cancer patients in therapeutic follow-up (TG) and ten women without comorbidities (CG) participated in the study (46±8.87 years old). Both groups were evaluated at two time points, before and 20 weeks after the start of chemotherapy. Functional capacity and muscle strength were assessed by 6-minute walk test (6MWT) and handgrip test, respectively. Autonomic function was assessed by heart rate variability analysis. RESULTS: TG presented greater reductions in the handgrip test for the non-dominant hand (TG ↓15.2%; CG: ↑1.1%, p<0.05) compared to GC. However, no significant differences were found regarding VO2max (p>0.05) and 6MWT total distance (p>0.05). Regarding the heart rate variability variables before and after follow-up period, rMSSD (CG= 39.15±37.66; TG= 14.89±8.28, p= 0.01) and SDNN (CG= 55.77±40.03; TG= 26.30±10.37, p= 0.02) showed effect in the group and time interaction, whereas the LF/HF ratio presented significant difference only in the time analysis (CG= 2.24±2.30; TG= 2.84±1.82, p= 0.04). CONCLUSION: Chemotherapy used in the treatment of breast cancer patients resulted in decreased muscle strength and autonomic imbalance. The data suggests that chemotherapy may carry the risk of developing cardiovascular disease. TRIAL REGISTRATION: Registration not required.

Effects of FFP2/N95 face mask on low- and high-load resistance exercise performance in recreational weight lifters.

COVID-19 pandemic, has led to several countries adopting the use of masks in public spaces. Mask used during physical exercise it may induce early fatigue. However, despite the results with aerobic exercise, as far as we know, no studies have been carried out on wearing a mask during resistance exercise.This randomized, crossover study verified the acute effect of an FFP2/N95 face mask on moderate- and high-load upper body resistance exercise performance in recreational weight lifters.The FFP2/N95 face mask impacted performance, evaluated with bar velocity, in the high-intensity resistance bench press exercise until movement failure but decreased oxygen saturation and increased rate of perceived effort only in the moderate-intensity exercise.

Differences in Nervous Autonomic Control in Response to a Single Session of Exercise in Bodybuilders Using Anabolic Androgenic Steroids.

Considering the role of autonomic nerve activity in blood pressure control, this study aimed to investigate the cardiac autonomic nerve responses after an aerobic exercise session in Anabolic Androgenic Steroids (AAS) users. Twenty men (AAS, n = 9; control group, n = 11) performed an aerobic exercise session (60 min, 70 to 80% of HRmax). Heart rate variability (HRV) was assessed before and during a 60-min post-exercise recovery period. RMSSD (root mean square successive difference of the RR intervals) and the LF/HF ratio (low frequency/high frequency spectra) were also evaluated. The Student's t-test for independent samples was used to compare differences between initial group characteristics. Repeated measures ANOVA was used to compare pre- and post-exercise HRV recovery (p < 0.05). AAS had a lower SDNN (standard deviation of the intervals) (40.8 ± 16.8 vs. 71.6 ± 24.7 ms; p = 0.04, d = 1.4) and a higher LF/HF (3.4 ± 2.1 vs. 1.8 ± 0.9%; p = 0.03, d = 0.9) before exercise. AAS and controls had similar RMSSD (14.0 ± 15.8 vs. 18.9 ± 12.1 ms; p = 0.20) and a LF/HF (2.8 ± 1.6 vs. 2.4 ± 1.2 ms; p = 0.41) immediately post-exercise. The between-groups comparison revealed a higher HF/LF at 30 min (4.3 ± 1.4 vs. 2.5 ± 1.3%; p = 0.008, d = 1.3) and 60 min (5.0 ± 2.2 vs. 2.3 ± 0.8%; p = 0.001, d = 1.6) for the AAS group in the recovery time. This study demonstrated impaired parasympathetic activity at rest and immediately after the exercise session as an adverse effect of AAS usage, but similar behavior regarding the restoration of sympathetic activity.