Does sex mediate the affective response to high intensity interval exercise?

No Sex Differences in Perceptual Responses to High-Intensity Interval Training or Sprint Interval Training

ABSTRACT

Coe, LN and Astorino, TA. No sex differences in perceptual responses to high-intensity interval training or sprint interval training. J Strength Cond Res 36(6): 1025-1032, 2024-High-intensity interval training (HIIT) elicits similar and, in some cases, superior benefits vs. moderate-intensity continuous training (MICT). However, HIIT is typically more aversive than MICT because of the higher intensity and in turn, greater blood lactate accumulation (BLa). This study explored potential sex differences in perceptual responses to acute HIIT and sprint interval training. Fifteen men (age and V̇O2max = 29 ± 8 years and 39 ± 3 ml·kg-1·min-1) and 13 women (age and V̇O2max = 22 ± 2 years and 38 ± 5 ml·kg-1·min-1) who are healthy and recreationally active initially underwent testing of maximal oxygen uptake (V̇O2max) on a cycle ergometer. In randomized order on 3 separate occasions, they performed the 10 × 1-minute protocol at 85% of peak power output, 4 × 4-minute protocol at 85-95% maximal heart rate (%HRmax), or reduced exertion high intensity interval training consisting of 2 "all-out" 20-second sprints at a load equal to 5% body mass. Before and throughout each protocol, rating of perceived exertion (rating of perceived exertion [RPE] 6-20 scale), affective valence (+5 to -5 of the Feeling Scale), and BLa were assessed. Five minutes postexercise, enjoyment was measured using the Physical Activity Enjoyment scale survey. Results showed no difference in RPE (p = 0.17), affective valence (0.27), or enjoyment (p = 0.52) between men and women. Blood lactate accumulation increased in response to all protocols (p < 0.001), and men showed higher BLa than women (p = 0.03). Previous research suggests that interval exercise protocols are not interchangeable between men and women, yet our data reveal that men and women having similar V̇O2max exhibit no differences in perceptual responses to interval exercise.

Cardiorespiratory Fitness and Performance Adaptations to High-Intensity Interval Training: Are There Differences Between Men and Women? A Systematic Review with Meta-Analyses

BACKGROUND

It is important to consider biological sex as a variable that might influence exercise adaptation in order to optimize exercise prescription for men and women.

OBJECTIVE

The aim of this study was to quantify the impact of biological sex on maximal oxygen uptake ([Formula: see text]O2max) and performance outcomes after high-intensity interval training (HIIT).

METHODS

A systematic search and review was conducted by two independent reviewers up to 8 September 2022 using MEDLINE, SPORTDiscus, and Sports Medicine & Education Index in ProQuest. Trials including healthy adults were included if they presented data for or compared male and female [Formula: see text]O2max or performance outcomes in response to HIIT. Performance outcomes included measures of exercise performance and concurrently measured physiological adaptations. Where appropriate, a random-effects, pre-post meta-analysis was undertaken. Data were sub-grouped for men and women, baseline training level, mean age, intervention type, and intervention length. Heterogeneity was assessed using Chi2, Cochran's Q, and Higgins I2 and sensitivity analyses, where required. Study quality was assessed using the Newcastle-Ottawa Scale and publication bias was assessed through visual inspection of funnel plots.

RESULTS

Thirty-three references from 28 trials were included in the review (n = 965; 462 women and 503 men). Meta-analyses included 19 studies for [Formula: see text]O2max, eight for peak power output from [Formula: see text]O2max testing (PPO), and five for threshold power (powerAT). Meta-analyses revealed similar increases in [Formula: see text]O2max in women (g = 0.57; 95% CI 0.44-0.69) and men (g = 0.57; 95% CI 0.42-0.72), and powerAT in women (g = 0.38; 95% CI 0.13-0.64) and men (g = 0.38; 95% CI 0.11-0.64). Raw mean differences for change in [Formula: see text]O2max were Δ 0.32 L·min-1 and 3.50 mL·kg-1·min-1 in men, versus Δ 0.20 L·min-1 and 3.34 mL·kg-1·min-1 for women. No significant sex differences were present for the primary analysis of any outcome. After sub-grouping, significant differences were present for PPO where the effect size was higher for well-trained women (g = 0.37) compared with well-trained men (g = 0.17), and for [Formula: see text]O2max where interventions with a duration of 4 weeks or less had significantly smaller effect sizes compared with those longer than 4 weeks (p < 0.001). Unweighted mean percentage change in [Formula: see text]O2max, PPO, and powerAT across studies was 11.16 ± 7.39%, 11.16 ± 5.99%, and 8.07 ± 6.55% for women, and 10.90 ± 5.75%, 8.22 ± 5.09%, and 7.09 ± 7.17% for men, respectively. Significant heterogeneity was present for both [Formula: see text]O2max and PPO (I2, range: 62.06-78.80%). Sub-grouping by baseline training status and intervention length decreased heterogeneity in most groups. A qualitative synthesis of other outcomes indicated similar improvements in fitness and performance for men and women with some evidence suggesting differences in the mechanisms of adaptation.

LIMITATIONS AND RISK OF BIAS

Publication bias is unlikely to have significantly influenced results for [Formula: see text]O2max or powerAT, but the meta-analysis of PPO could have benefitted from additional study data to strengthen results. The overlap in age categories and sensitivity of the analysis limits the accuracy of the results of the sub-grouping by age.

CONCLUSIONS

Findings indicated no sex-specific differences for any fitness or performance outcomes. Baseline training status and intervention length accounted for most variability in outcomes. PROSPERO registration number: CRD42021272615.

Burpee Interval Training Is Associated With a More Favorable Affective Valence and Psychological Response Than Traditional High Intensity Exercise

Acute psychological responses to physical activity may help explain long-term adherence to it. Thus, we compared acute psychological responses to different exercise protocols with identical durations. Eighteen moderately active young adults [ Mage = 23, SD = 3 years; MVO2max (maximum oxygen consumption) = 42.8, SD = 4.3 mL·kg−1·min−1; MBMI (body mass index) = 24, SD = 2 kg·m−2] completed three low-volume exercise sessions in a crossover research design: (a) sprint interval training (SIT), (b) burpee interval training (BIT) requiring 10 × 5 second efforts with 35 seconds of passive recovery, and (c) a single bout of vigorous intensity continuous training (VICT) requiring 6 minutes and 5 seconds of running at ∼85% of peak heart rate (HRpeak). We assessed participants’ ratings of perceived exertion (RPE), affective valence, enjoyment, intention, preference, and self-reported recovery and wellness before, during, and after each session. BIT was associated with significantly greater enjoyment, preference, and exercise intention (at 5 × week) than VICT ( p ≤ .05). SIT elicited greater RPE ( M = 5.38, SD = 2.00) than both BIT ( M = 2.88, SD = 1.23) and VICT ( M = 3.55, SD = 1.38) ( p ≤ .05), and we observed a higher increase in RPE over time with SIT versus BIT ( p = .019). For affective valence, SIT ( M = 0.55, SD = 2.12) elicited a more aversive response than both BIT ( M = 2.55, SD = 1.09) and VICT ( M = 1.94, SD = 1.51) ( p ≤ .05), and there was a higher increase in this aversive response to SIT over time ( p < .05). Forty-eight-hour postexercise session muscle soreness was significantly lower with VICT than with BIT ( p = .03). Overall, BIT was associated with more positive psychological responses than SIT and VICT.

Affecting Effects on Affect: The Impact of Protocol Permutations on Affective Responses to Sprint Interval Exercise; A Systematic Review and Meta-Analysis of Pooled Individual Participant Data

Responses to sprint interval exercise (SIE) are hypothesized to be perceived as unpleasant, but SIE protocols are diverse, and moderating effects of various SIE protocol parameters on affective responses are unknown. We performed a systematic search to identify studies (up to 01/05/2021) measuring affective valence using the Feeling Scale during acute SIE in healthy adults. Thirteen studies involving 18 unique trials and 316 unique participant (142 women and 174 men) affective responses to SIE were eligible for inclusion. We received individual participant data for all participants from all studies. All available end-of-sprint affect scores from each trial were combined in a linear mixed model with sprint duration, mode, intensity, recovery duration, familiarization and baseline affect included as covariates. Affective valence decreased significantly and proportionally with each additional sprint repetition, but this effect was modified by sprint duration: affect decreased more during 30 s (0.84 units/sprint; 95% CI: 0.74–0.93) and 15–20 s sprints (1.02 units/sprint; 95% CI: 0.93–1.10) compared with 5–6 s sprints (0.20 units/sprint; 95% CI: 0.18–0.22) (both p < 0.0001). Although the difference between 15–20 s and 30 s sprints was also significant (p = 0.02), the effect size was trivial (d = −0.12). We observed significant but trivial effects of mode, sprint intensity and pre-trial familiarization, whilst there was no significant effect of recovery duration. We conclude that affective valence declines during SIE, but the magnitude of the decrease for an overall SIE session strongly depends on the number and duration of sprints. This information can be applied by researchers to design SIE protocols that are less likely to be perceived as unpleasant in studies of real-world effectiveness.

Differences in Physiological and Perceptual Responses to High Intensity Interval Exercise Between Arm and Leg Cycling

This study compared changes in oxygen uptake (VO₂), heart rate (HR), blood lactate concentration (BLa), affective valence, and rating of perceived exertion (RPE) between sessions of high intensity interval exercise (HIIE) performed on the arm (ACE) and leg cycle ergometer (LCE). Twenty three active and non-obese men and women (age and BMI=24.7±5.8year and 24.8±3.4kg/m²) initially underwent graded exercise testing to determine VO₂max and peak power output (PPO) on both ergometers. Subsequently on two separate days, they performed 10 1min intervals of ACE or LCE at 75 %PPO separated by 1min of active recovery at 10 %PPO. Gas exchange data, HR, and perceptual responses were obtained continuously and blood samples were acquired pre- and post-exercise to assess the change in BLa. VO₂max and PPO on the LCE were significantly higher (p<0.001) than ACE (37.2±6.3 vs. 26.3±6.6ml/kg/min and 259.0±48.0 vs. 120.0±48.1W). Mean VO₂ (1.7±0.3 vs. 1.1±0.3L/min, d=2.3) and HR (149±14 vs. 131±17 b/min, d=2.1) were higher (p<0.001) in response to LCE vs. ACE as was BLa (7.6±2.6 vs. 5.3±2.5mM, d=2.3), yet there was no difference (p=0.12) in peak VO₂ or HR. Leg cycling elicited higher relative HR compared to ACE (81±5 vs. 75±7 %HRmax, p=0.01), although, there was no difference in relative VO₂ (63±6 vs. 60±8 %VO₂max, p=0.09) between modes. Affective valence was lower during LCE vs. ACE (p=0.003), although no differences in enjoyment (p=0.68) or RPE (p=0.59) were demonstrated. Overall, HIIE performed on the cycle ergometer elicits higher relative heart rate and blood lactate concentration and a more aversive affective valence, making these modes not interchangeable in terms of the acute physiological and perceptual response to interval based exercise.

The effect of menstrual cycle and exercise intensity on psychological and physiological responses in healthy eumenorrheic women

Psychological responses such as affect, mood, motivation, anxiety are important considerations for exercise adherence. A large body of evidence indicates that exercise intensity is a controllable variable capable of increasing positive feelings. Investigations thus far, however, have not considered that the higher incidence of negative psychological responses in women could be due to physiological particularities of the menstrual cycle (MC). This project investigates the effect of MC phases and exercise intensity on psychophysiological responses in fourteen healthy, eumenorrheic and physically active women. Measuring psychophysiological responses before, during and after exercise, participants completed two exercise bouts of 15 min above and below the anaerobic threshold in the follicular phase (FP) and the luteal phase (LP) of the MC. Lower levels of depression and hostility and higher levels of vigor, affect and motivation were observed during exercise in the FP. Exercise at moderate intensity elicited more positive psychological responses compared to high-intensity exercise, highlighted by findings that affect and rating of perceived exertion were worse in the LP without changes in physiological responses. These findings suggest no effect of MC on physiological responses, but psychological responses are impaired in the LP, worsening particularly during exercise at high intensity.

Positive Affective and Enjoyment Responses to Four High-Intensity Interval Exercise Protocols

Several variables can be manipulated to compose high-intensity interval exercise (HIIE) protocols, and these different combinations may evoke different psychological responses (affect, enjoyment, mood, and perceived exertion). This study investigated psychological responses during four HIIE protocols. Following anthropometric measurements and two maximal exercise tests, 23 physically inactive adults (11 males [M_age = 25.6, SD = 4.8 years; M_{body mass} = 68.5, SD = 12.2 kg; M_height = 1.72, SD = 0.08 m] and 12 females [M_age = 25.0, SD = 3.5 years; M_{body mass} = 57.2, SD = 8.7 kg; M_height = 1.59, SD = 0.06 m]) performed four different types of HIIE on different days: (a) Long-interval HIIE (HIIE_L-10 × 60 seconds:60 seconds), (b) Short-interval HIIE (HIIE_S-2 blocks of 10 × 30 seconds:30 seconds with 120 seconds between blocks), (c) Repeated Sprint Training (19 × 6 seconds all out:40 seconds), and (d) Sprint Interval Training (4 × 30 seconds all-out efforts: 240 seconds). We used a final session to assess participants' HIIE preference. We recorded participant reports of affect, mood, and perceived exertion throughout protocols, and we recorded enjoyment after exercise session. Perceived exertion significantly increased across all HIIE protocols (p < .001), with higher values in the first quartile during Sprint Interval Training versus HIIE_L (p = .033). Affective response presented higher values pre-exercise and at the first quartile compared with all other moments (p < .001). Tension (p < .001) and depression (p = .013) decreased from pre- to post-exercise in all experimental conditions. At pre-exercise, female participants were tenser than males (p = .018), though males presented higher pre-exercise vigor scores than females (p = .023). Vigor increased over time for females (p = .022). Enjoyment did not vary between sexes or protocols. Participants expressed a higher preference for Repeated Sprint Training. HIIE protocols promoted positive psychological responses for physically inactive young adults, and exercise designs may modulate psychological responses.

Acute Sprint Interval Exercise Increases Both Cognitive Functions and Peripheral Neurotrophic Factors in Humans: The Possible Involvement of Lactate

There is increasing attention to sprint interval exercise (SIE) training as a time-efficient exercise regime. Recent studies, including our own (Kujach et al., 2018), have shown that acute high-intensity intermittent exercise can improve cognitive function; however, the neurobiological mechanisms underlying the effect still remain unknown. We thus examined the effects of acute SIE on cognitive function by monitoring the peripheral levels of growth and neurotrophic factors as well as blood lactate (LA) as potential mechanisms. Thirty-six young males participated in the current study and were divided into two groups: SIE (n = 20; mean age: 21.0 ± 0.9 years) and resting control (CTR) (n = 16; mean age: 21.7 ± 1.3 years). The SIE session consisted of 5 min of warm-up exercise and six sets of 30 s of all-out cycling exercise followed by 4.5 min of rest on a cycling-ergometer. Blood samples to evaluate the changes of serum concentrations of brain-derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1), vascular endothelial growth factor (VEGF), and blood LA were obtained at three time points: before, immediately after, and 60 min after each session. A Stroop task (ST) and trail making test (TMT) parts A and B were used to assess cognitive functions. Acute SIE shortened response times for both the ST and TMT A and B. Meanwhile, the peripheral levels of BDNF, IGF-1, and VEGF were significantly increased after an acute bout of SIE compared to those in CTR. In response to acute SIE, blood LA levels significantly increased and correlated with increased levels of BDNF, IGF-1, and VEGF. Furthermore, cognitive function and BDNF are found to be correlated. The current results suggest that SIE could have beneficial effects on cognitive functions with increased neuroprotective factors along with peripheral LA concentration in humans.

Blood Lactate Concentration Is Not Related to the Increase in Cardiorespiratory Fitness Induced by High Intensity Interval Training

Background: There is individual responsiveness to exercise training as not all individuals experience increases in maximal oxygen uptake (VO₂max), which does not benefit health status considering the association between VO₂max and mortality. Approximately 50% of the training response is genetic, with the other 50% accounted for by variations in dietary intake, sleep, recovery, and the metabolic stress of training. This study examined if the blood lactate (BLa) response to high intensity interval training (HIIT) as well as habitual dietary intake and sleep duration are associated with the resultant change in VO₂max (ΔVO₂max). Methods: Fourteen individuals (age and VO₂max = 27 ± 8 years and 38 ± 4 mL/kg/min, respectively) performed nine sessions of HIIT at 130% ventilatory threshold. BLa was measured during the first and last session of training. In addition, sleep duration and energy intake were assessed. Results: Data showed that VO₂max increased with HIIT (p = 0.007). No associations occurred between ΔVO₂max and BLa (r = 0.44, p = 0.10), energy intake (r = 0.38, p = 0.18), or sleep duration (r = 0.14, p = 0.62). However, there was a significant association between training heart rate (HR) and ΔVO₂max (r = 0.62, p = 0.02). Conclusions: When HIIT is prescribed according to a metabolic threshold, energy intake, sleep status, and BLa do not predict ΔVO₂max, yet the HR response to training is associated with the ΔVO₂max.