Sex Differences in Heart Rate Variability Responses to Eight Weeks of Circuit Training
Circuit Training and Autonomic Recovery: Sex Differences in Heart Rate Variability Among Inactive Young Adults
The main goal of this study is to find out how an 8-week circuit training exercise program affects heart health and how the body recovers in young adults who do not regularly exercise. The researchers also want to see if these responses are different between men and women.
The body's nervous system controls automatic functions like heart rate. Measuring changes in heart rate patterns-known as heart rate variability (HRV)-helps show how well the body switches between "fight-or-flight" (stress/exercise mode) and "rest-and-digest" (recovery mode). While men and women naturally have different heart rate patterns at rest, less is known about whether they recover differently after a structured exercise program.
The main questions this study aims to answer are:
- Does 8 weeks of circuit training improve heart rate recovery and nervous system balance in inactive young adults?
- Do men and women show different heart rate responses or recovery patterns after taking part in circuit training?
To answer these questions, inactive university students took part in an 8-week supervised circuit training program. Participants were considered inactive if they did less than 150 minutes of moderate exercise or less than 75 minutes of vigorous exercise per week.
Participants completed 20 exercise sessions (2 times per week) led by the study team:
- Exercise Sessions: Each session started with a 5-minute warm-up, followed by 10 exercise stations using light weights, resistance bands, and bodyweight movements. Exercises targeted both upper and lower body muscles.
- Workouts and Rest: Participants did each exercise for 30 seconds, rested for 1 minute between stations, and rested for 5 minutes between full sets.
- Progression: During Weeks 1 to 4, participants did 2 sets per session. During Weeks 5 to 8, they increased to 3 sets per session.
To measure heart rate recovery, participants wore a heart rate chest monitor while resting quietly lying down:
- Before starting the 8-week program (Baseline)
- At 10 minutes after a workout at Week 8 (Short-term recovery)
- At 24 hours after a workout at Week 8 (Full recovery)
The researchers compared the heart rate data between men and women across these time points to see how quickly their nervous systems returned to a resting state after exercise.
Visão geral do estudo
Status
Condições
Intervenção / Tratamento
Descrição detalhada
This study evaluates the effects of an 8-week supervised circuit training program on heart rate variability (HRV) and autonomic recovery patterns among physically inactive young adults, with a specific focus on sex-related differences.
Participants undergo an 8-week exercise intervention consisting of 20 total sessions scheduled twice per week. The intervention follows a progressive volume design:
- Weeks 1 to 4: Participants perform 2 complete sets per session (8 sessions total).
- Weeks 5 to 8: Participants perform 3 complete sets per session (12 sessions total).
Each exercise session begins with a 5-minute dynamic warm-up. The circuit consists of 10 sequential exercise stations targeting major upper-body and lower-body muscle groups using body weight, resistance bands, and dumbbells: 1. Heel raises with dumbbells 2. Lateral raises with resistance bands 3. Leg abductions with resistance bands 4. Shoulder extensions and flexions with resistance bands 5. Jump rope 6. Triceps extensions with dumbbells 7. Half squats with resistance bands 8. Standing chest fly with dumbbells 9. Leg curls with resistance bands 10. Bicep curls with dumbbells
Participants perform each exercise station for 30 seconds, followed by a 1-minute rest interval between stations. A 5-minute rest period is provided between complete circuits. All sessions take place under direct supervision.
Autonomic function is evaluated via continuous beat-to-beat R-R interval recordings using a validated heart rate monitor while participants rest quietly in a supine position in a climate-controlled room (21 °C). Heart rate variability is assessed across three specific time points:
- Baseline: Pre-intervention assessment prior to beginning the 8-week training protocol.
- Post-10 Minutes: Immediate post-exercise recovery assessment within 10 minutes following the final training session at Week 8.
- Post-24 Hours: Delayed recovery assessment 24 hours following the final training session at Week 8.
Extracted frequency-domain HRV parameters include Low Frequency (LF: 0.04-0.15 Hz), High Frequency (HF: 0.15-0.40 Hz), and the LF/HF ratio, analyzed in both absolute power values (ms2) and normalized units (n.u.). Comparisons are conducted between male and female participants across time points to analyze sex-specific autonomic adaptations and recovery trajectories following circuit training.
Tipo de estudo
Inscrição (Real)
Estágio
- Não aplicável
Contactos e Locais
Locais de estudo
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Kelantan
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Kubang Kerian, Kelantan, Malásia, 16150
- Exercise and Sports Science Laboratory, Universiti Sains Malaysia
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Critérios de participação
Critérios de elegibilidade
Idades elegíveis para estudo
Aceita Voluntários Saudáveis
Gêneros Elegíveis para o Estudo
Descrição
Inclusion Criteria:
- Physically inactive, defined as engaging in less than 150 minutes of moderate-intensity aerobic activity or less than 75 minutes of vigorous-intensity activity per week.
- Enrolled university student.
- Willing and able to provide informed consent and attend supervised training sessions twice per week for 8 weeks.
Exclusion Criteria:
- Regular engagement in structured exercise or training programs.
- Current consumption of dietary supplements.
- Inability or unwillingness to refrain from caffeine, alcohol, and vigorous physical activity for 24 hours prior to heart rate variability (HRV) testing sessions.
Plano de estudo
Como o estudo é projetado?
Detalhes do projeto
- Finalidade Principal: Ciência básica
- Alocação: Não randomizado
- Modelo Intervencional: Atribuição Paralela
- Mascaramento: Nenhum (rótulo aberto)
Armas e Intervenções
Grupo de Participantes / Braço |
Intervenção / Tratamento |
|---|---|
|
Experimental: Male Group
Male participants undergoing an 8-week supervised circuit training intervention (2 sessions per week; 2 sets per session for weeks 1-4, 3 sets per session for weeks 5-8). |
Participants complete an 8-week supervised circuit training intervention consisting of 20 total sessions (2 sessions per week). Each session begins with a 5-minute warm-up, followed by 10 exercise stations targeting both upper-body and lower-body muscle groups using body weight, resistance bands, and dumbbells. The 10 stations include: heel raises with dumbbells, lateral raises with resistance bands, leg abductions with resistance bands, shoulder extensions and flexions with resistance bands, jump rope, triceps extensions with dumbbells, half squats with resistance bands, standing chest fly with dumbbells, leg curls with resistance bands, and bicep curls with dumbbells. Each exercise station is performed for 30 seconds with a 1-minute rest interval between stations, and a 5-minute rest interval between complete sets. Training volume progresses from 2 sets per session in Weeks 1-4 (8 sessions) to 3 sets per session in Weeks 5-8 (12 sessions)
Outros nomes:
|
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Experimental: Female Group
Female participants undergoing the identical 8-week supervised circuit training intervention (2 sessions per week; 2 sets per session for weeks 1-4, 3 sets per session for weeks 5-8). |
Participants complete an 8-week supervised circuit training intervention consisting of 20 total sessions (2 sessions per week). Each session begins with a 5-minute warm-up, followed by 10 exercise stations targeting both upper-body and lower-body muscle groups using body weight, resistance bands, and dumbbells. The 10 stations include: heel raises with dumbbells, lateral raises with resistance bands, leg abductions with resistance bands, shoulder extensions and flexions with resistance bands, jump rope, triceps extensions with dumbbells, half squats with resistance bands, standing chest fly with dumbbells, leg curls with resistance bands, and bicep curls with dumbbells. Each exercise station is performed for 30 seconds with a 1-minute rest interval between stations, and a 5-minute rest interval between complete sets. Training volume progresses from 2 sets per session in Weeks 1-4 (8 sessions) to 3 sets per session in Weeks 5-8 (12 sessions)
Outros nomes:
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O que o estudo está medindo?
Medidas de resultados primários
Medida de resultado |
Descrição da medida |
Prazo |
|---|---|---|
|
Change in Low-Frequency (LF) Power in Normalized Units (LF n.u.)
Prazo: Measured at Baseline (Week 0), Post-10 minutes (Week 8), and Post-24 hours (Week 8).
|
Frequency-domain heart rate variability metric reflecting combined sympathetic and parasympathetic autonomic modulation (measured in normalized units, n.u.). |
Measured at Baseline (Week 0), Post-10 minutes (Week 8), and Post-24 hours (Week 8).
|
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Change in High-Frequency (HF) Power in Normalized Units (HF n.u.)
Prazo: Measured at Baseline (Week 0), Post-10 minutes (Week 8), and Post-24 hours (Week 8).
|
Frequency-domain heart rate variability metric reflecting parasympathetic (vagal) autonomic modulation (measured in normalized units, n.u.) |
Measured at Baseline (Week 0), Post-10 minutes (Week 8), and Post-24 hours (Week 8).
|
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Change in Low-Frequency to High-Frequency Ratio (LF/HF Ratio)
Prazo: Measured at Baseline (Week 0), Post-10 minutes (Week 8), and Post-24 hours (Week 8).
|
Ratio of LF power to HF power, used as an index of sympathovagal balance during recovery. |
Measured at Baseline (Week 0), Post-10 minutes (Week 8), and Post-24 hours (Week 8).
|
Colaboradores e Investigadores
Patrocinador
Investigadores
- Investigador principal: Marilyn Li Yin Ong, PhD, Universiti Sains Malaysia
Publicações e links úteis
Publicações Gerais
- Heart rate variability: standards of measurement, physiological interpretation and clinical use. Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Circulation. 1996 Mar 1;93(5):1043-65. No abstract available.
- Shaffer F, Ginsberg JP. An Overview of Heart Rate Variability Metrics and Norms. Front Public Health. 2017 Sep 28;5:258. doi: 10.3389/fpubh.2017.00258. eCollection 2017.
- Ramos-Campo DJ, Andreu Caravaca L, Martinez-Rodriguez A, Rubio-Arias JA. Effects of Resistance Circuit-Based Training on Body Composition, Strength and Cardiorespiratory Fitness: A Systematic Review and Meta-Analysis. Biology (Basel). 2021 Apr 28;10(5):377. doi: 10.3390/biology10050377.
- Kappus RM, Ranadive SM, Yan H, Lane-Cordova AD, Cook MD, Sun P, Harvey IS, Wilund KR, Woods JA, Fernhall B. Sex differences in autonomic function following maximal exercise. Biol Sex Differ. 2015 Dec 1;6:28. doi: 10.1186/s13293-015-0046-6. eCollection 2015.
- Koenig J, Thayer JF. Sex differences in healthy human heart rate variability: A meta-analysis. Neurosci Biobehav Rev. 2016 May;64:288-310. doi: 10.1016/j.neubiorev.2016.03.007. Epub 2016 Mar 7.
- Ibrahim NS, Muhamad AS, Chen CK, & Ooi FK. (2022) Effects of probiotics consumption and resistance exercise on bone metabolism markers in physically inactive young males. Malays J Sport Sci Recreat 18(1), 92. https://doi.org/10.24191/mjssr.v18i1.17643
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Palavras-chave
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Outros números de identificação do estudo
- USM/JEPeM/KK/25010089
Plano para dados de participantes individuais (IPD)
Planeja compartilhar dados de participantes individuais (IPD)?
Descrição do plano IPD
Individual participant data (IPD) will not be shared to maintain participant privacy and confidentiality. All relevant aggregated datasets generated and analyzed during the current study are provided within the results section of the published article.
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