Abstract

Purpose: This exploratory study aimed to examine the potential effects of a 12-week progressive whole-body resistance exercise training (RET) program on measured submaximal oxygen consumption (submaximal VO2) and work efficiency during the 6-min walk test (6MWT) in healthy postmenopausal women and breast cancer survivors. Methods: Twenty-four postmenopausal women (Healthy, HEA; 54 ± 3 years; BMI 26.6 ± 2.7 kg·m?2; n = 13 and breast cancer survivors, BCS; 52 ± 5 years; BMI 26.8 ± 2.1 kg·m?2; n = 11) completed a 12-week RET program. Participants were assessed using the 6MWT with a PNOE® metabolic analyzer before and after the intervention. Metabolic and respiratory parameters, including submaximal VO2 and work efficiency were measured. Data were analyzed using repeated measures ANOVA. Results: Twelve-week RET improved the distance covered in the 6MWT by 10 ± 11% in the HEA group (from 586.6 ± 27.9 to 642.9 ± 35.9 m) and by 6 ± 16% in the BCS group (from 572.9 ± 62.6 to 604.7 ± 39.9 m) (P < 0.001; ?2 = 0.54), with no significant differences between the groups (P = 0.175). There was an increase in RER (P < 0.001), ventilation (P = 0.043), and carbohydrate percentage (P < 0.001), along with a decrease in fat consumption percentage (P < 0.001), with no differences between groups (P > 0.05). After 12 weeks of RET, absolute submaximal VO2 decreased in both groups (P < 0.001), with no differences between them (P > 0.05). The maximum work rate increased (P < 0.001), with no differences between groups (P > 0.05). Work efficiency also improved over time (P < 0.05), with no differences between groups (P > 0.05). Conclusion: As an exploratory analysis, these findings suggest that a 12-week RET program improved work efficiency and reduced measured submaximal VO2 during the 6MWT in both populations. The improvements were similar in healthy postmenopausal women and breast cancer survivors. Trial registration number: NCT05690295. © The Author(s) 2025.