Relationship between Oxygen Uptake, Heart Rate, and Perceived Effort in an Aquatic Incremental Test in Older Women

Cadence (steps/min) and relative intensity in 61 to 85-year-olds: the CADENCE-Adults study

BACKGROUND

We previously demonstrated that a heuristic (i.e., evidence-based, rounded yet practical) cadence threshold of ≥ 100 steps/min was associated with absolutely-defined moderate intensity physical activity (i.e., ≥ 3 metabolic equivalents [METs]) in older adults 61-85 years of age. Although it was difficult to ascertain achievement of absolutely-defined vigorous (6 METs) intensity, ≥ 130 steps/min was identified as a defensible threshold for this population. However, little evidence exists regarding cadence thresholds and relatively-defined moderate intensity indicators, including ≥ 64% heart rate [HR] maximum [HRmax = 220-age], ≥ 40% HR reserve [HRR = HRmax-HRresting], and ≥ 12 Borg Scale Rating of Perceived Exertion [RPE]; or vigorous intensity indicators including ≥ 77%HRmax, ≥ 60%HRR, and ≥ 14 RPE.

PURPOSE

To analyze the relationship between cadence and relatively-defined physical activity intensity and identify relatively-defined moderate and vigorous heuristic cadence thresholds for older adults 61-85 years of age.

METHODS

Ninety-seven ostensibly healthy adults (72.7 ± 6.9 years; 49.5% women) completed up to nine 5-min treadmill walking bouts beginning at 0.5 mph (0.8 km/h) and progressing by 0.5 mph speed increments (with 2-min rest between bouts). Directly-observed (and video-recorded) steps were hand-counted, HR was measured using a chest-strapped monitor, and in the final minute of each bout, participants self-reported RPE. Segmented mixed model regression and Receiver Operating Characteristic (ROC) curve analyses identified optimal cadence thresholds associated with relatively-defined moderate (≥ 64%HRmax, ≥ 40%HRR, and ≥ 12 RPE) and vigorous (≥ 77%HRmax, ≥ 60%HRR, and ≥ 14 RPE) intensities. A compromise between the two analytical methods, including Youden's Index (a sum of sensitivity and specificity), positive and negative predictive values, and overall accuracy, yielded final heuristic cadences.

RESULTS

Across all relatively-defined moderate intensity indicators, segmented regression models and ROC curve analyses identified optimal cadence thresholds ranging from 105.9 to 112.8 steps/min and 102.0-104.3 steps/min, respectively. Comparable values for vigorous intensity indicators ranged between126.1-132.1 steps/min and 106.7-116.0 steps/min, respectively. Regardless of the relatively-defined intensity indicator, the overall best heuristic cadence threshold aligned with moderate intensity was ≥ 105 steps/min. Vigorous intensity varied between ≥ 115 (greater sensitivity) or ≥ 120 (greater specificity) steps/min.

CONCLUSIONS

Heuristic cadence thresholds align with relatively-defined intensity indicators and can be useful for studying and prescribing older adults' physiological response to, and/or perceived experience of, ambulatory physical activity.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02650258. Registered 24 December 2015.

Aerobic physical exercise versus dual-task cognitive walking in cognitive rehabilitation of people with stroke: a randomized clinical trial

Introduction

Stroke is a neurological deficit caused by an acute focal injury to the central nervous system due to vascular injury that can result in loss of neurological function, lasting brain damage, long-term disability and, in some cases, death. The literature reports that aerobic physical exercise, as well as dual-task cognitive walking, are used for the cognitive recovery of people with stroke. We aimed to assess whether aerobic physical exercise influences post-stroke cognitive recovery, namely performance on selective and sustained attention. We tested the hypothesis that post-stroke aerobic physical exercise leads to more significant gains than post-stroke dual-task cognitive walking.

Methods

We used a Randomized Clinical Trial, single-blind, parallel group, to verify the existence of differences between two groups. A total of 34 patients with subacute to chronic stroke were divided into two groups to train three times a week for 12 weeks: the aerobic physical exercise (PE) group engaged in 20 min on a treadmill, 20 min on a stationary bicycle and 5 min on a desk bike pedal exerciser per session; the dual-task (DT) gait exercise group walked for 45 min while simultaneously performing cognitive tasks per session. All participants were assessed on cognitive functioning with the Mini-Mental State Examination (MMSE) and d2 Test of Attention before acute interventions and post interventions. We have also applied a Visual Analog Scale to monitor the participants' perceived difficulty, pre-, post-acute, and post-chronic interventions. Participants also responded to a Borg Scale of perceived exertion following the acute and the final session of chronic training.

Results

A mixed model ANOVA revealed a significant interaction effect with a large effect size for most of the cognitive variables under study. The variables associated with the d2 Test of Attention showed significant differences between the groups, mainly from T0 to T2. Also for MMSE, an ANOVA revealed a significant interaction effect with significant improvements from T0 to T2. Our results strongly suggest that aerobic physical exercise is more beneficial than dual-task cognitive-gait exercise since in the PE group, cognitive attention scores increase, and cognitive impairment and perception of exertion decrease, compared to the DT group.

Conclusion

These findings support that PE provides more significant benefits for patients post-stroke when compared to DT.

Cardiorespiratory Parameters Comparison Between Incremental Protocols Performed in Aquatic and Land Environments by Healthy Individuals: A Systematic Review and Meta-Analysis

BACKGROUND

Physical properties of water cause physiological changes in the immersed human body compared with the land environment. Understanding the magnitude of cardiorespiratory alterations might ensure adequate intensity control during aquatic exercise programs.

OBJECTIVE

We aimed to compare the oxygen uptake (VO₂), heart rate (HR), and rating of perceived exertion (RPE) parameters during aquatic and land incremental tests.

METHODS

Four databases (PubMed, LILACS, EMBASE, and SPORTDiscus) were searched in September 2020. Eligibility criteria included studies in a crossover design comparing aquatic and land incremental tests for healthy individuals with at least one of the following parameters: VO₂ (maximal, VO_2max; anaerobic threshold, VO_2AT), HR (HR_max; HR_AT), and RPE (RPE_max; RPE_AT). The random-effects meta-analysis included mean difference and 95% confidence interval for VO₂ and HR or standardized mean difference for RPE. The Joanna Briggs Institute Critical Appraisal tool was adapted to assess methodological quality.

RESULTS

Twenty-eight studies were eligible and included in the meta-analysis. Aquatic protocols showed lower values compared with land for VO_2max (- 7.07 mL.kg^-1.min^-1; - 8.43 to - 5.70; n = 502), VO_2AT (- 6.19 mL.kg^-1.min^-1; - 7.66 to - 4.73; n = 145), HR_max (- 11.71 bpm; - 13.84 to - 9.58; n = 503), and HR_AT (- 15.29 bpm; - 19.05 to - 11.53; n = 145). RPE_max (0.01; - 0.16 to 0.18; n = 299) and RPE_AT (- 0.67; - 1.35 to 0.02; n = 55) values were similar between aquatic and land protocols.

CONCLUSIONS

Our study reinforces the specificity of the environment during incremental tests for prescribing exercises based on physiological parameters as VO₂ and HR parameters presented lower values in aquatic protocols than land protocols. Conversely, RPE seems an interchangeable measure of exercise intensity, with similar values during the protocols in both environments. Substantial levels of heterogeneity were present for the VO_2max and HR_max meta-analyses, and as such, results should be interpreted with attention. PROTOCOL REGISTRATION: This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD42020212508).

Locus coeruleus neurons encode the subjective difficulty of triggering and executing actions

The brain stem noradrenergic nucleus locus coeruleus (LC) is involved in various costly processes: arousal, stress, and attention. Recent work has pointed toward an implication in physical effort, and indirect evidence suggests that the LC could be also involved in cognitive effort. To assess the dynamic relation between LC activity, effort production, and difficulty, we recorded the activity of 193 LC single units in 5 monkeys performing 2 discounting tasks (a delay discounting task and a force discounting task), as well as a simpler target detection task where conditions were matched for difficulty and only differed in terms of sensory-motor processes. First, LC neurons displayed a transient activation both when monkeys initiated an action and when exerting force. Second, the magnitude of the activation scaled with the associated difficulty, and, potentially, the corresponding amount of effort produced, both for decision and force production. Indeed, at action initiation in both discounting tasks, LC activation increased in conditions associated with lower average engagement rate, i.e., those requiring more cognitive control to trigger the response. Decision-related activation also scaled with response time (RT), over and above task parameters, in line with the idea that it reflects the amount of resources (here time) spent on the decision process. During force production, LC activation only scaled with the amount of force produced in the force discounting task, but not in the control target detection task, where subjective difficulty was equivalent across conditions. Our data show that LC neurons dynamically track the amount of effort produced to face both cognitive and physical challenges with a subsecond precision. This works provides key insight into effort processing and the contribution of the noradrenergic system, which is affected in several pathologies where effort is impaired, including Parkinson disease and depression.

Psychological Effects of Motivational Aquatic Resistance Interval Training and Nutritional Education in Older Women

Several studies have demonstrated the positive effects of physical exercise programs on physical and mental health throughout life. It is necessary to know the factors that contribute to the well-being of older adults in order to achieve healthy aging. The aim of this study was to evaluate the relationship between well-being perception and the use of autonomy supportive coaching behaviours across a motivational aquatic resistance interval training program. Thirty-four women over 65 years of age from the province of Alicante, Spain, participated, and were randomly assigned to: motivational aquatic resistance interval training group (MART; age: 69.6 ± 5.01 years, height: 1.62 ± 7.88 m, weight: 75.3 ± 12.8 kg) and control group (CG; age: 67.7 ± 3.60 years, height: 1.54 ± 5.47 m, weight: 66.9 ± 10.2 kg). The MART program was conducted for 14 weeks, with three training sessions/week. The CG did not perform any physical activity during the study. Perception of autonomy support was assessed through the Autonomy-Supportive Coaching Questionnaire (ASCQ), Psychological needs by the Basic Psychological Needs in Exercise Scale (BPNES), Intrinsic motivation to exercise was assessed through Intrinsic Motivation Inventory (IMI) and Perception of Physical Activity by the International physical activity questionnaire (IPAQ). In MART, compared to CG, significant differences were observed in BPNS, IMI and IPAQ questionnaires used, except in the ASCQ. The differences were significant in all three cases in BPNS (p < 0.05 in autonomy and competence and p = 0.001 in relationship with others), obtaining better scores after intervention than previously. As for the IMI scale, significant differences were also obtained in both subscales. The level of physical activity also improved significantly, with higher scores on the IPAQ after the intervention than before (p < 0.001). In conclusion, when practitioners perceive greater well-being, satisfaction of their basic psychological needs, greater self-selection, volition, and autonomy instead of pressure, demand and control, the result is better behaviour with greater psychological well-being, adherence and consequent health benefits.

Benefits of Adding an Aquatic Resistance Interval Training to a Nutritional Education on Body Composition, Body Image Perception and Adherence to the Mediterranean Diet in Older Women

The human population is increasing due to lengthening life expectancy, but the quality of life and health of people is moving in the opposite direction. The purpose of this study is to evaluate how aquatic resistance interval training can influence body composition, body image perception and adherence to the Mediterranean diet (MD) in older women participants in a nutrition education program and to study the relation between these variables. Thirty-four participants aged 69 ± 4 years were randomly assigned into two groups: experimental (aquatic resistance interval training plus nutritional intervention) and control (nutritional intervention). The intervention consisted of resistance training in an aquatic environment carried out for 14 weeks (three sessions per week; 60 min each). Body composition, body image perception and adherence to MD diet were evaluated at baseline and 14 weeks. No significant differences were found between groups regarding body image perception and adherence to the MD. There was a significant increase in muscle mass (kg) (p < 0.001) and a significant decrease in fat mass (kg) (p < 0.001) in the intervention group when compared to the control group. The addition of aquatic resistance interval training to a nutritional intervention was not sufficient to change body image perception and adherence to MD but produced improvement in body composition (through an increase in muscle mass and decrease on fat mass) in older women.