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.
Descripción general del estudio
Estado
Condiciones
Intervención / Tratamiento
Descripción detallada
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 estudio
Inscripción (Actual)
Fase
- No aplica
Contactos y Ubicaciones
Ubicaciones de estudio
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Kelantan
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Kubang Kerian, Kelantan, Malasia, 16150
- Exercise and Sports Science Laboratory, Universiti Sains Malaysia
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Criterios de participación
Criterio de elegibilidad
Edades elegibles para estudiar
Acepta Voluntarios Saludables
Géneros elegibles para el estudio
Descripción
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.
Plan de estudios
¿Cómo está diseñado el estudio?
Detalles de diseño
- Propósito principal: Ciencia básica
- Asignación: No aleatorizado
- Modelo Intervencionista: Asignación paralela
- Enmascaramiento: Ninguno (etiqueta abierta)
Armas e Intervenciones
Grupo de participantes/brazo |
Intervención / Tratamiento |
|---|---|
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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)
Otros nombres:
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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)
Otros nombres:
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¿Qué mide el estudio?
Medidas de resultado primarias
Medida de resultado |
Medida Descripción |
Periodo de tiempo |
|---|---|---|
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Change in Low-Frequency (LF) Power in Normalized Units (LF n.u.)
Periodo de tiempo: Measured at Baseline (Week 0), Post-10 minutes (Week 8), and Post-24 hours (Week 8).
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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.)
Periodo de tiempo: 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)
Periodo de tiempo: Measured at Baseline (Week 0), Post-10 minutes (Week 8), and Post-24 hours (Week 8).
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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).
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Colaboradores e Investigadores
Patrocinador
Investigadores
- Investigador principal: Marilyn Li Yin Ong, PhD, Universiti Sains Malaysia
Publicaciones y enlaces útiles
Publicaciones Generales
- 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
Fechas de registro del estudio
Fechas importantes del estudio
Inicio del estudio (Actual)
Finalización primaria (Actual)
Finalización del estudio (Actual)
Fechas de registro del estudio
Enviado por primera vez
Primero enviado que cumplió con los criterios de control de calidad
Publicado por primera vez (Actual)
Actualizaciones de registros de estudio
Última actualización publicada (Actual)
Última actualización enviada que cumplió con los criterios de control de calidad
Última verificación
Más información
Términos relacionados con este estudio
Palabras clave
Términos MeSH relevantes adicionales
Otros números de identificación del estudio
- USM/JEPeM/KK/25010089
Plan de datos de participantes individuales (IPD)
¿Planea compartir datos de participantes individuales (IPD)?
Descripción del plan 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.
Información sobre medicamentos y dispositivos, documentos del estudio
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