Comparing Vascular Responses to Resistance Exercise with and Without Blood Flow Restriction in Young and Older Adults

Официальное название

Comparing Macro- and Microvascular Responses to Acute Resistance Exercise with and Without Blood Flow Restriction in Young and Older Adults: a Parallel Group Crossover Randomized Trial

Обзор

Aging leads to declines in functional capacity and effort tolerance. Muscle strength remains stable from ages 25 to 50 but declines significantly after age 60, affecting activities like stair climbing and walking, reducing autonomy and independence. While muscle atrophy is a significant factor, macrovascular endothelial dysfunction also impairs skeletal muscle performance in older adults. Nitric oxide (NO), produced by endothelial cells, regulates vascular homeostasis and contractile function. NO enhances muscle fiber shortening velocity, reduces twitch time-to-peak contraction, and increases the rate of force development. Aging-related endothelial dysfunction reduces NO availability, leading to reduced muscle mass and sarcopenia via decreased skeletal muscle perfusion. Increased arterial stiffness disrupts ventricular-vascular coupling, reducing cardiac output and contributing to age-related muscle weakness. Additionally, microvascular function decreases with age, contributing to altered physical work perception and reduced function. Low capillary density is linked to reduced walking speed in older adults and reduced walking time in peripheral arterial disease patients, supporting the microvasculature\'s role in functional performance. Reduced muscle mass also increases central hemodynamic load, impacting arterial stiffness and cardiac function. Resistance training (RT) is recommended to mitigate aging effects like loss of strength and muscle mass and reduce cardiovascular risk and all-cause mortality. Guidelines suggest 1-3 sets of 8-12 repetitions at 60-80% of the individual\'s repetition maximum (1RM), performed at least twice a week. However, older adults with osteoarthritis and cardiovascular conditions often cannot tolerate high mechanical stress and are prescribed lower intensity-resistance training (LIRT) at 40-50% of 1RM, typically yielding negligible muscle hypertrophy or strength gains. Blood flow restriction (BFR) training, which applies pressure bands to restrict blood flow during LIRT, increases muscle volume and strength. While BFR shows promise, it can cause acute increases in arterial stiffness and blood pressure in older adults, necessitating caution in its prescription. This study aims to compare macrovascular and microvascular function responses to acute resistance exercise with and without BFR in young and older adults. We hypothesize that older adults will show a more pronounced increase in macrovascular and microvascular dysfunction following resistance exercise compared to younger participants. In this parallel group randomized controlled trial, participants will be randomly assigned to either LIRT-BFR or high-intensity resistance training (HIRT). Each participant will attend three sessions: a familiarization session and two experimental sessions involving the randomized exercise conditions. Measurements of brachial blood pressure, heart rate, and macrovascular and microvascular function will be taken at rest and during recovery periods post-exercise.

Подробное описание

In this parallel group crossover randomized trial, young and older adults participants will be randomly assigned to 2 experimental conditions: a LIRT+BFR and HIRT. These two conditions were chosen because acute LIRE+BFR and HIRE have been shown to increase similarly heart rate and blood pressure in older adults. Each participant will report to the Laboratory on 3 occasions, at least 1 week apart. In visit 1, participants will have their body weight and height measured, and be evaluated twice for macro- and microvascular function within 30 min at resting condition (control). After that, they will become acquainted with the exercise protocol and determine their one-repetition maximum (1RM) for the bilateral leg press exercise and knee extension. In visits 2 and 3, participants will perform the experimental conditions in a simple randomized order, to which participants will be blinded until arrival at the laboratory.

The allocation sequence will be generated by Dr. XM, using a web-generated simple randomization scheme (http://www.randomizer.org/), and placed in sequentially numbered, opaque, sealed envelopes to ensure concealment of the allocation process and minimize potential biases to researchers and participants, delivered to field researchers, who will be blind, on the day of the first visit.

Each session will begin with 15 minutes of supine rest on a cushioned examination table. This will be followed by: 1) assessment of brachial blood pressure, heart rate and microvascular function at rest as measured by finger photoplethysmography (Vicorder, Berlin, Germany). Following these assessments, participants will engage in one of the previously randomized resistance training experimental conditions for roughly 30 min. After that, participants immediately return to the examination table and will recover in the supine position for 30 minutes, during which brachial blood pressure, heart rate and microvascular function will be re-evaluated 5-, 30-min intervals into recovery and compared to those at rest. Post-exercise time measurements are aimed to characterize the post-exercise biphasic response of the microvascular function.

Participants will be instructed to avoid caffeine and alcohol for 24 hours, and fully void before the session. They will also be advised to avoid vigorous exercise-related activities 24 hours before each session, including the familiarization session. All evaluations will be led by 4 physiotherapy students per participant (4:1), with over 30h of training in the evaluation and training protocols. During the participant\'s time in the laboratory, a certified professional in basic life support and automated external defibrillators (AEDs), will be present at the clinic.

Based upon an effect size of 0.141 derived from the mean and dispersion response of carotid-radial pulse wave velocity to Non-Autoregulated Blood Flow Restriction resistance exercise. 48 participants are required, (24 per group), matched for sex, assuming a 5% alpha error, and 20% beta error, with a 1:1 ratio between groups. To account for a 10% dropout rate, a total of 52 will be recruited.

Young adults at Egas Moniz School of Health \& Science will be recruited through Instagram ads and strategically placed posters. Interested individuals will use a QR code to access a form with study details and eligibility criteria. Eligible participants will receive an electronic informed consent form to sign before their first visit. Older adults will be recruited from local senior centers, gyms, and community programs via email. Those who meet the eligibility criteria will receive a printed informed consent form to sign before their first clinic visit.

Вмешательства

• Другое Low intensity-resistance training with lower limb blood flow restriction
  In the LIRT-BFR, participants will perform 4 sets of 20 bilateral leg presses and knee extensions repetitions with BFR at 30% of 1-RM, with 30-second rest intervals between sets, in an estimated total of 30-minute session per participant. Cuffs will be placed in the upper thighs and inflated with a pressure that is 1.3 times the individual's ankle systolic blood pressure in the data collection day for the entirety of the training session with a commercial cuff (width×length; 11×85 cm, SC10™, Hok
• Другое High Intensity Resistance Training
  In the HIRT participants will perform bilateral leg presses and knee extension without BFR at 75% of one-repetition maximum (1-RM), for 3 sets of 10 reps, with 2-minute rest intervals, in an estimated total of 30-minute session per participant.

Первичные конечные точки

• Change in macrovascular function [Срок оценки: At rest and re-evaluated 5- and 30-minutes into recovery following the experimental conditions]
• Change in central arterial stiffness [Срок оценки: At rest and re-evaluated 5- and 30-minutes into recovery following the exercise condition]
• Change in blood pressure [Срок оценки: at rest and re-evaluated after each set and 5- and 30-minutes into recovery following the exercise condition]
• Change in microvascular function [Срок оценки: At rest and re-evaluated 5- and 30-minutes into recovery following the exercise condition]

Критерии участия

Критерии включения

• Aged between 18-30 years and those over 60 years.

Критерии исключения

• Past or current history of coronary heart disease, stroke, oncological disease, or major cardiovascular events.
• Individuals who had undergone surgery within the last two months
• Body mass index (BMI) greater than 30 kg/m²
• Declared sleep apnea
• Active kidney or liver disease
• Active tobacco smokers
• Sensory impairments
• Neurological or orthopedic functional impairments, musculoskeletal pathologies affecting exercise capacity
• Physically active for more than six months with a weekly activity level of 1,000 MET/min.

Критерии приведены из реестра в оригинале (на английском). Окончательную оценку соответствия проводит исследовательский центр.

Здоровые добровольцы: Да

Дизайн исследования

Распределение

Рандомизированное

Модель

Перекрёстный дизайн

Маскирование

Открытое

Основная цель

Поддерживающая терапия

Центры проведения

Португалия · 2 центра

• Egas Moniz School of Health and Science — Almada
• Egas Moniz School of Health and Science — Almada

Публикации

• Fahs CA, Rossow LM, Thiebaud RS, Loenneke JP, Kim D, Abe T, Beck TW, Feeback DL, Bemben DA, Bemben MG. Vascular adaptations to low-load resistance training with and without blood flow restriction. Eur J Appl Physiol. 2014 Apr;114(4):715-24. doi: 10.1007/s00421-013-2808-3. Epub 2013 Dec 31. PMID 24375201
• Horiuchi M, Stoner L, Poles J. The effect of four weeks blood flow restricted resistance training on macro- and micro-vascular function in healthy, young men. Eur J Appl Physiol. 2023 Oct;123(10):2179-2189. doi: 10.1007/s00421-023-05230-3. Epub 2023 May 28. PMID 37245196
• Rolnick N, Licameli N, Moghaddam M, Marquette L, Walter J, Fedorko B, Werner T. Autoregulated and Non-Autoregulated Blood Flow Restriction on Acute Arterial Stiffness. Int J Sports Med. 2024 Jan;45(1):23-32. doi: 10.1055/a-2152-0015. Epub 2023 Aug 10. PMID 37562444
• Liu Y, Jiang N, Pang F, Chen T. Resistance Training with Blood Flow Restriction on Vascular Function: A Meta-analysis. Int J Sports Med. 2021 Jun;42(7):577-587. doi: 10.1055/a-1386-4846. Epub 2021 Mar 18. PMID 33735919
• Pereira-Neto EA, Lewthwaite H, Boyle T, Johnston K, Bennett H, Williams MT. Effects of exercise training with blood flow restriction on vascular function in adults: a systematic review and meta-analysis. PeerJ. 2021 Jul 7;9:e11554. doi: 10.7717/peerj.11554. eCollection 2021. PMID 34277146
• Zhang T, Tian G, Wang X. Effects of Low-Load Blood Flow Restriction Training on Hemodynamic Responses and Vascular Function in Older Adults: A Meta-Analysis. Int J Environ Res Public Health. 2022 May 31;19(11):6750. doi: 10.3390/ijerph19116750. PMID 35682336
• Sardeli AV, do Carmo Santos L, Ferreira MLV, Gaspari AF, Rodrigues B, Cavaglieri CR, Chacon-Mikahil MPT. Cardiovascular Responses to Different Resistance Exercise Protocols in Elderly. Int J Sports Med. 2017 Nov;38(12):928-936. doi: 10.1055/s-0043-115737. Epub 2017 Sep 26. PMID 28950398
• Dvoretskiy S, Lieblein-Boff JC, Jonnalagadda S, Atherton PJ, Phillips BE, Pereira SL. Exploring the Association between Vascular Dysfunction and Skeletal Muscle Mass, Strength and Function in Healthy Adults: A Systematic Review. Nutrients. 2020 Mar 7;12(3):715. doi: 10.3390/nu12030715. PMID 32156061

Идентификаторы

NCT: NCT06596304 · HOLD TIGHT

Первоисточники (государственные реестры)

• ClinicalTrials.gov (NIH, США)

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