Response to Exercise Training During Cardiac Rehabilitation Differs by Sex

Abstract

Purpose: Directly measured peak aerobic capacity or oxygen uptake ( ) is a powerful predictor of prognosis in individuals with cardiovascular disease. Women enter phase 2 cardiac rehabilitation (CR) with lower and their response to training, compared with men, is equivocal. We analyzed at entry and exit in patients participating in CR and improvements by diagnosis to assess training response. We also identified sex differences that may influence change in . Methods: The cohort included consecutive patients enrolled in CR between January 1996 and December 2015 who performed entry exercise tolerance tests. Data collected included demographics, index diagnosis, , and exercise training response. Results: The cohort consisted of 3925 patients (24% female). There was a significant interaction between baseline and diagnosis (P < .001), with percutaneous coronary intervention and myocardial infarction greater than other diagnoses. Surgical patients demonstrated greater improvement in than nonsurgical diagnoses (n = 1789; P < .001). Women had lower than men for all diagnoses (P < .02) and demonstrated less improvement (13 vs 17%, P < .001). Percent improvement using estimated metabolic equivalents of task (METs) were similar for women and men (33 vs 31%, P = NS). Despite overall increases in , 18% of patients (24% women, 16% men) failed to demonstrate any improvement (exit ≤ entry ). Conclusions: While there were no differences in training effect estimated by METs, directly measured showed a significantly lower training response for women despite adjusting for covariates. In addition, 18% of patients did not see any improvement in . Alternatives to traditional CR exercise programming need to be considered.

Sex Differences in Cardiac Rehabilitation Outcomes

“…Further, a higher percentage of females failed to increase VO 2 peak from pre to post-CR compared with males (24% versus 16%). 57 These findings support the notion that established CR exercise prescription practices (based primarily on data from males) may result in females receiving suboptimal exercise dosage. 67 It is likely that females (as well as males not exhibiting VO 2 peak improvement) require a greater duration of CR (ie, more CR sessions), higher exercise intensity, and increased frequency of these CR sessions to achieve VO 2 peak improvement 58,61,68 ; however, future studies are clearly needed to confirm this hypothesis.…”

Sex differences in physical and mental health following high-intensity interval training in adults with cardiovascular disease who completed cardiac rehabilitation

“…HIIT evaluations presenting outcomes by sex are scarce, with small sample sizes (particularly of females), inconsistent findings (Sandercock et al 2013;Witvrouwen et al 2019;Rengo et al 2020;Trachsel et al 2020;Way et al 2021), and often fail to measure mental health outcomes (Lee et al 2018;Terada et al 2019a;Rengo et al 2020;Way et al 2021). Our meta-analysis in patients with coronary artery disease revealed smaller absolute improvements in VȮ 2 peak, BMI and fasting plasma glucose in females than males following HIIT (Way et al 2021).…”

“…There is a paucity of sex-based evaluations of HIIT (Lee et al 2018;Terada et al 2019a;Rengo et al 2020;Trachsel et al 2020;Way et al 2021). Our primary finding aligns with an analysis of randomized trials including MICT and HIIT which did not find time by sex interactions in VȮ 2 peak with (∆ females: 1.9±2.5; males: 2.9±3.5 mL/kg/min, p=0.255) or without (∆ females: 1.1±2.1; males: 2.0±2.6 mL/kg/min, p=0.116) lean body mass adjustment (Trachsel et al 2020).…”

“…The main limitation of our study is the estimation of VȮ 2 peak from ACSM equations instead of measuring it directly with ergospirometry; this approach is associated with a higher measurement error (Jang et al 2020), but is an affordable (Grace et al 2016b) and valid method to capture VȮ 2 peak improvements in cardiovascular populations (American College of Sports Medicine 2020). When possible, future sex-specific studies should utilize directly measured gas analysis to benefit from the greater sensitivity, which may be key for sex comparisons (Rengo et al 2020). Our participants were fairly young, mostly Caucasian D r a f t and well-educated, limiting the generalizability of our findings beyond these populations.…”

“…Although the meta-D r a f t analysis showed no sex differences when comparing relative VȮ 2 peak expressed as a percentage (Way et al 2021). A large CR study (n=3,925, 24% female) where 34% of participants (20% females) engaged in HIIT found smaller improvements in VȮ 2 peak in females than males when using directly measured gas analysis (13% vs. 17%, p<0.001), but this was not observed when reporting VȮ 2 peak as estimated peak METs from treadmill time (33% vs. 31%) (Rengo et al 2020). We could speculate that the variability associated with estimating VȮ 2 peak (Jang et al 2020) may have influenced why we did not observe a sex difference in the current study.…”