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Background: Physical exercise can help prolong healthy aging, yet few options enable older adults to exercise at very high intensities at home. A previous gym-based supramaximal High Intensity interval Training (HIT) protocol on stationary bicycles has shown promising results. Core components were supramaximal interval intensity that could be systematically modulated (controlled, individualized, escalated, and de-escalated) and protocol safety. In this exploratory co-creation study with older adults, we aimed to adapt the supramaximal HIT protocol for potential future implementation in older adults' home settings.

Methods: Eleven older adults (6 females; ages 69–74) with prior supramaximal HIT experience participated in this two-phase co-creation study. In phase one, co-creators engaged in workshops to identify, explore, and discuss available home-based training modalities. In phase two, co-creators took part in lab tests wherein suitable modalities were tested and compared to stationary bicycling regarding acute physiological responses and safety during a supramaximal HIT session (10 × 10-second intervals with 50-second passive recovery). Results were continuously merged with the protocol's core components.

Results: Physiological and emotional reactions to HIT, potential exercise modalities, and necessary protocol adaptations were identified in phase one. When merged with core components three modalities - walking up steps, chair stand, and rubber band cross country double poling - were selected for phase two testing. Of these, chair stand elicited physiological responses most comparable to stationary bicycling, while fulfilling all core components.

Conclusions: We adapted a researcher-supervised watt-controlled supramaximal HIT-protocol on stationary bicycles to a chair stand protocol with audio metronome-controlled intensity for potential implementation at home. This adaptation is the first step towards a safe and scalable implementation of a home-based supramaximal HIT program for older adults.

Heart rate variability (HRV), a marker of cardiovascular health, declines with aging and physical inactivity. We compared the effects of supramaximal high-intensity interval training (HIT) with brief intervals and moderate-intensity training (MIT) on HRV in non-exercising older adults. Sixty-eight participants were randomized to 12 weeks of supervised cycling performed twice weekly: supramaximal HIT (10 × 6-s intervals) or MIT (3 × 8-min intervals), with training intensity individually prescribed and progressively increased over the intervention using external power output. HRV was assessed using time-domain indices (SDNN, RMSSD, and LnRMSSD) and resting heart rate from 5-min segments, derived from 10-min recordings collected in participants' homes on seven consecutive days at baseline and follow-up. Between-group differences in change favored supramaximal HIT for SDNN (5.4 ms [95% CI: 1.1–9.7]), RMSSD (3.5 ms [0.7–6.3]), and LnRMSSD (0.15 [0.01–0.28]). Within-group changes showed an increase in RMSSD in the HIT group (2.0 ms [0.1–4.0]) and a decrease in SDNN in the MIT group (−3.1 ms [−6.2 to −0.1]). Resting heart rate did not differ between groups. In conclusion, supramaximal HIT induced more favorable HRV adaptations than MIT in non-exercising older adults.

Background: Extrapulmonary manifestations including cognitive impairment, reduced muscle and cardiovascular function is common in COPD. While high-intensity exercise offers extrapulmonary benefits, its implementation in COPD is challenging. This randomised cross-over trial examined the feasibility and physiological responses of a novel supramaximal high-intensity interval-training (SupraHIIT) protocol compared to moderate-intensity continuous training (MICT) in people with COPD and matched healthy controls (HCs).

Methods: Sixteen people with COPD and 16 HCs performed SupraHIIT and MICT. SupraHIIT consisted of 10x6 sec intervals at ≈150% and ≈200% of maximum aerobic power (MAP), while MICT was performed for 20 min at 60% of MAP. Outcomes were exercise intensity, change in exerkines, feasibility, and cardiorespiratory demand of the modalities.

Results: SupraHIIT was feasible and enabled up to a 3.5-fold increase in external exercise intensity compared to MICT (184±66 and 245±88 watt versus 71±22 watt in COPD, p<0.001). All participants could complete SupraHIIT which was the preferred modality in both groups (p<0.01) while 5/16 participants with COPD interrupted MICT due to intolerable dyspnea or exhaustion (p=0.005). Both modalities increased plasma brain-derived neurotrophic factor (pBDNF) by an average of 59% (range 30%-87%, p<0.05). When normalised for duration at target power, SupraHIIT produced a 5–10-fold greater increase than MICT. Both modalities lead to a variable response in other exerkines including clusterin, lactate, hepatocyte growth factor and interleukin-6.

Conclusion: In COPD, short duration SupraHIIT is more feasible and enables markedly higher external exercise intensities than MICT. By elevating pBDNF and other potentially beneficial exerkines, it shows potential for extrapulmonary benefits.

Background Cognitive impairment is increasingly recognized as an extrapulmonary manifestation of COPD, yet little is known across cognitive domains and associations with exercise capacities and inflammation remain underexplored.

Aims and objectives: To compare cognitive function in COPD and age-, sex- and physical activity matched healthy controls (HCs) and examine associations with exercise performance and systemic inflammation.

Methods: Multi-domain cognitive function was assessed at baseline in 44 individuals with COPD and 39 matched HCs. Correlations of exercise performance including CPET Wpeak and anaerobic capacity (Borg cycle strength test [BCST Wpeak]) and inflammation were analysed.

Results: COPD participants exhibited lower cognitive function across most domains compared to HCs (Table 1). In COPD, BCST Wpeak correlated with trail making tests ([TMT] TMT-A: r=-.43; TMT-B: r=-.32; p<0.05)) visual processing (VP1: r=.43; p<0.05) and memory (PAL: r=.35; p<0.05), while CPET Wpeak showed no associations. Higher fibrinogen levels correlated with poorer TMT-B and PAL1 performance (r=.38 & r=-.40; p<0.05).

Conclusion: Cognitive impairment spans across multiple domains in COPD, even in those with relatively preserved fitness and lung function. Cognitive deficits were associated to anaerobic, but not aerobic exercise capacity and were associated with systemic inflammation in some, but not all domains.

Background: Physical activity and exercise are promoted worldwide as effective interventions for healthy ageing. Various exercise initiatives have been developed and evaluated for their efficacy and effectiveness among older populations. However, a deeper understanding of participants’ experiences with these initiatives is crucial to foster long-term activity and exercise among older persons.

Methods: A constructivist grounded theory study was conducted to explore the experiences of older persons participating in a supervised group supramaximal high-intensity training (HIT) programme. Four focus groups were held, involving 28 persons aged 65 to 78. The focus groups were analysed inductively, followed by an iterative process of abstraction, abduction, and theory generation using a constant comparative method. A conceptual framework comprising three theoretical concepts—stereotype embodiment, ageist practices, and self-efficacy—was employed during the abductive phase as an analytical lens.

Results: The core category of our grounded theory, Negotiating a physically active life in tune with ageing, encapsulates the complex processes and actions influencing older persons as they engage in physical activities in their daily lives and in relation to HIT. This core category was created from the conceptual framework and the four categories: Grit in the moment and overall life, Empowered by the training group, Navigating one’s physically active self, and Committing to exercise for duty and pleasure. Participants reported feeling invigorated by the exercise, enjoying the challenge, and valuing the group setup for its social connectedness and structure. The generated theory illustrates how participants’ engagement with physical activity and exercise is shaped by various perspectives accumulated over their lifespan. The findings provide a plausible explanation of how participation in HIT groups can challenge negative age stereotypes and ageist practices while enhancing self-efficacy for high-intensity exercise.

Conclusions: Our grounded theory underscores that physical activity and exercise should be regarded as multifaceted processes, which must be considered when promoting physical activity initiatives for older persons. By considering the older person and societal norms and values, we can gather knowledge to design physical exercise interventions that are not only effective but also enjoyable and capable of transforming how individuals perceive themselves as exercising persons.

Background: Supramaximal high-intensity interval training (HIT) programmes can be challenging to replicate outside research settings. This study aimed to explore its feasibility for older adults in a community setting, incorporating perspectives from exercise participants and instructors.

Methods: A pragmatic feasibility study using a convergent mixed- methods design involving four exercise instructors from one training facility and 21 older adult exercise participants (14 women, age-range 65–78). The previously used HIT programme consisted of 20-minute sessions that included a warm-up, ten 6-second intervals, and cool-down. Instructors first adapted the programme around these core components to their setting and then conducted 25 sessions. Both qualitative (individual interviews) and quantitative (estimated maximal oxygen consumption, estimated 6-second power, exercise- related motivation, and self-efficacy) data were collected and analysed (content analysis and descriptive statistics) in parallel. A taxonomy for implementation outcomes was used as an analytical matrix.

Results: Experiences of both participants and instructors revealed that the structure of the training was regarded as engaging, enjoyable, and supportive for establishing routines and promoting ownership of training progression. Participants found personalised and motivating approaches to engage with the programme and confidence in their abilities grew. Changes in exercise-related motivation and self-efficacy showed individual variation without a group trend. Participants who completed the intervention showed a positive median change in estimated 6-second power and maximal oxygen consumption, although individual responses varied. Experienced challenges included coordinating tasks during intervals and confidence in managing the programme. Barriers to fidelity and to scale-up were related to the practical complexity and fixed structure.

Conclusions: Supramaximal HIT can be implemented for older adults in a community setting with appropriate support, including individualised watt-based intensity and structured progression. The findings highlight how participants took ownership of their intensity progression, enabling them to challenge their limits. However, the fixed structure and complexity in managing short intervals may pose barriers to broader adoption. To enhance feasibility and scalability, simplifying interval management and providing clear, structured guidance are recommended. These insights help refine and optimize supramaximal HIT implementation for older adults in community settings.

Trial registration: Open Science Framework 31 January 2023 (https://doi.org/10.17605/OSF.IO/B7T2G).

Accurate prescription of supramaximal exercise requires exercise tests covering the intensity domain between maximal aerobic and peak power output. All-out tests are commonly used for this objective but are considered challenging for people with chronic obstructive pulmonary disease (COPD) due to the extreme physiological demand. The modified Borg cycle strength test (mBCST), previously used in older adults to achieve supramaximal intensities, might be a suitable alternative in people with COPD. We aimed to determine the feasibility of the mBCST in people with COPD and to compare the physiological response with that of healthy older adults. Eighteen people with COPD and 16 age-, sex- and physical activity-matched healthy adults performed a cardiopulmonary exercise test and a mBCST. The mBCST is an incremental test [30 s:30 s cycling:rest; with individualized starting load and step size (15-50 W)] with end-of-test criteria of a rating of perceived exertion of >= 17 or cadence of <75 RPM for >5 s. Feasibility was assessed using a framework covering the aim, interpretability, familiarity, duration, scoring/completion complexity, costs and safety. Measurements of external exercise intensity, rating of perceived exertion, symptoms and cardiorespiratory demand were obtained. The mBCST was deemed feasible according to the feasibility framework. Expressed relative to the cardiopulmonary exercise test, all participants reached supramaximal external exercise intensities during the mBCST [COPD, 145 (125-168)%; healthy, 154 (148-163)%], without differences in intensity or physiological response between groups (p > 0.05). The mBCST is feasible in people with COPD and enables supramaximal external exercise intensities, with similar physiological response to healthy older adults. The mBCST could be considered when selecting an exercise test to prescribe supramaximal exercise.

Physical exercise shows positive effects on cognitive functions such as working memory (WM) for older adults; however, large individual differences in response exist and the underlying mechanisms are not well understood. We tested the hypothesis that exercise-induced changes in cardiorespiratory fitness and leg strength would improve WM-related brain activity, which subsequently would improve WM performance. This study was based on the Umeå HIT study, a randomized controlled trial assessing the effects of watt-controlled supramaximal high-intensity interval training (HIT) versus moderate-intensity training for nonexercising older adults (N=68). A subsample (n=43, 66 to 79 years, 56% females) underwent task-based functional magnetic resonance imaging, testing WM. The outcomes of interest were change in WM performance, WM task activation, cardiorespiratory fitness, and leg strength. For WM performance, we found no significant between-group difference in change; however, there was a significant within-group increase for HIT in WM composites. For HIT, changes in leg strength significantly predicted increased right dorsolateral prefrontal cortex activation, which in turn predicted improved in-scanner WM task performance. Cardiorespiratory fitness did not predict WM-related functional change. These results indicate a specific physiological ingredient, namely leg strength gains, that is a potential mechanism in exercise-induced prefrontal activation and WM performance increases.

Background: A novel concept of controlled, short-duration supramaximal HIIT enables 3-4 times higher exercise intensities with reduced dyspnea, compared to moderate-intensity continuous training (MICT) in people with COPD. However, its effects on neurotrophic factors and brain health are yet to be investigated. We aimed to examine the acute response of neurotrophic factors to supramaximal HIIT and MICT in people with COPD.

Methods: Sixteen people with mild to severe COPD (75±6 years; 73±13 FEV1%pred) underwent supramaximal HIIT (comprising 10x6 sec intervals interspersed with 54 sec rest) and MICT (20 min at 60% CPET Wpeak). Supramaximal HIIT was performed at two intensities (HIIT60% and HIIT80%). We measured plasma levels of brain-derived neurotrophic factor (BDNF), irisin, cathepsin B and clusterin pre- and post- exercise.

Results: BDNF increased after both HIIT and MICT (Fig 1). Clusterin increased during HIIT80% (19940 [−35900 to 49600] ng/mL, +11%, p=0.01) and MICT (23390 [−5060 to 51010] ng/mL, +12%, p=0.03), but not HIIT60% (−1100 [−10060 to 113600] ng/mL, -1%, p=0.85). No changes were seen in irisin or cathepsin B.

Conclusion: For the first time, we showed that in COPD, supramaximal HIIT induces a similar increase in BDNF as MICT, with half the exercise duration. Supramaximal HIIT might be a viable exercise modality in COPD, while its long-term effects on brain health remain to be investigated.

This analysis of secondary outcomes investigated the applicability of supramaximal high-intensity interval training (HIT) with individually prescribed external intensity performed on stationary bicycles. Sixty-eight participants with a median (min; max) age of 69 (66; 79), at the time not engaged in regular exercise were randomized to 25 twice-weekly sessions of supramaximal HIT (20-min session with 10 × 6-s intervals) or moderate-intensity training (MIT, 40-min session with 3 × 8-min intervals). The primary aim was outcomes on applicability regarding; adherence to prescribed external interval intensity, participant reported positive and negative events, ratings of perceived exertion (RPE 6–20), and affective state (Feeling Scale, FS -5–5). A secondary aim was to investigate change in exercise-related self-efficacy (Exercise Self-Efficacy Scale) and motivation (Behavioural Regulations in Exercise Questionnaire-2). Total adherence to the prescribed external interval intensity was [median (min; max)] 89 % (56; 100 %) in supramaximal HIT, and 100 % (95; 100 %) in MIT. The supramaximal HIT group reported 60 % of the positive (112 of 186) and 36 % of the negative (52 of 146) events. At the end of the training period, the median (min; max) session RPE was 15 (12; 17) for supramaximal HIT and 14 (9; 15) for MIT. As for FS, the median last within-session rating was 3 (−1; 5) for supramaximal HIT and 3 (1; 5) for MIT. Exercise-related motivation increased (mean difference in Relative Autonomy Index score = 1.54, 95 % CI [0.69; 2.40]), while self-efficacy did not change (mean difference = 0.55, 95 % CI [-0.75; 1.82]), regardless of group. This study provide support for supramaximal HIT in supervised group settings for older adults.