Effects of Cyclical Blood Flow Restriction Exercise on Muscle Hypertrophy and Capillaries in Older Adults

NCT07689487 | Completed

• 1 other identifier: TYL-2025-6950
• Study Type: interventional
• Target: 31
• Locations: 1 country
• Sites: 1

Brief Summary

The purpose of this study was to learn if low-load resistance exercise combined with cyclical blood flow restriction (BFR) could improve small blood vessel structure and muscle size in older adults. Skeletal muscle thinning and the loss of tiny blood vessels (capillaries) commonly happen as people age. While lifting heavy weights can help stop this, heavy loads are often not suitable for older adults with joint pain or other health conditions. Low-load exercise with BFR involves wearing inflatable cuffs on the upper arms that temporarily slow down blood flow, which can trigger positive changes in muscles and blood vessels without needing heavy weights. Researchers compared three groups of older adults:

• One group performed low-load upper-body exercises while wearing cyclical BFR cuffs.
• A second group performed the exact same exercises at the same low load but without wearing cuffs.
• A third group maintained their normal daily activities without participating in any structured exercise program. Participants in the exercise groups trained 3 days a week for 8 weeks. Researchers used video capillaroscopy (a specialized camera at the fingernail base) to examine changes in tiny blood vessels and ultrasound imaging to measure arm muscle thickness before and after the 8-week period.

Conditions

Aging; Muscle Atrophy; Sarcopenia in Elderly

Keywords

blood flow restriction; aging; nailfold capillaroscopy; muscle hypertrophy; angiogenesis; sarcopenia; KAATSU

Outcome Measures

Primary Outcomes (2)

• Nailfold Capillary Diameter

  Microvascular morphology changes measured at three anatomical regions: the arterial (afferent) limb, the apical portion, and the venous (efferent) limb using nailfold video capillaroscopy.

  Baseline and post-intervention (at the end of week 8)

• Upper-Arm Muscle Thickness

  Structural muscle hypertrophy of the biceps brachii and triceps brachii muscles of the dominant arm, assessed via B-mode ultrasonography.

  Baseline and post-intervention (at the end of week 8).

Secondary Outcomes (3)

• Total Body Mass

  Baseline and post-intervention (at the end of week 8)

• Body Fat Percentage

  Baseline and post-intervention (at the end of week 8)

• Fat Mass

  Baseline and post-intervention (at the end of week 8)

Study Arms (3)

Cyclical Blood Flow Restriction (BFR) Group

EXPERIMENTAL

Older adults who performed low-load upper-body resistance exercise (20-40% 1RM) combined with cyclical blood flow restriction using pneumatic cuffs (40 mm width, 8 cycles of 30 s inflation/5 s deflation). Sessions were performed 3 days per week for 8 weeks.

Device: Blood Flow Restriction (BFR); Behavioral: Conventional Low-Load Resistance Exercise

Low-Load Training Group

ACTIVE COMPARATOR

Older adults who performed the identical low-load upper-body resistance exercise protocol (4 exercises, 4x12 repetitions at 20-40% 1RM) 3 days per week for 8 weeks, but without wearing restriction cuffs.

Behavioral: Conventional Low-Load Resistance Exercise

Non-Exercise Control Grou

NO INTERVENTION

Older adults who maintained their habitual lifestyle and daily physical activities without participating in any structured resistance training program for 8 weeks.

Interventions

Blood Flow Restriction (BFR) DEVICE

Vascular restriction administered using an automated cyclical pneumatic device (KAATSU Cycle 2.0) with 40 mm cuffs placed proximally on both arms. Protocol consists of 8 cycles of 30 seconds of inflation followed by 5 seconds of deflation per cycle, individually calibrated by capillary refill time and verified by Doppler ultrasound.

Cyclical Blood Flow Restriction (BFR) Group

Conventional Low-Load Resistance Exercise BEHAVIORAL

Upper-body resistance exercise training encompassing four movements: biceps curl, triceps pushdown, lat pulldown, and chest press. Executed under a controlled 4x12 repetition scheme at an intensity of 20-40% 1RM, performed 3 days per week for a duration of 8 weeks.

Cyclical Blood Flow Restriction (BFR) Group; Low-Load Training Group

Eligibility Criteria

• Age: 50 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age 50 years or older.
• Recreationally active, defined as participating in light-to-moderate physical activity 2 or more days per week.
• No structured resistance training within the preceding six months.
• Free from cardiovascular disease, neurological conditions, or musculoskeletal injury contraindicating resistance exercise.
• Able to provide written informed consent before enrollment.

You may not qualify if:

• Current use of anticoagulant or vasoactive medication.
• History of deep vein thrombosis (DVT).
• Resting systolic blood pressure greater than 160 mmHg.

Sponsors & Collaborators

• Akdeniz University, Scientific Research Projects Coordination Unit: collaborator
• Akdeniz University: lead

Study Sites (1)

Akdeniz University, Faculty of Sport Sciences

Antalya, Antalya, 07058, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Muscular Atrophy; Sarcopenia

Interventions

Blood Flow Restriction Therapy

Condition Hierarchy (Ancestors)

Neuromuscular Manifestations; Neurologic Manifestations; Nervous System Diseases; Atrophy; Pathological Conditions, Anatomical; Pathological Conditions, Signs and Symptoms; Signs and Symptoms

Intervention Hierarchy (Ancestors)

Exercise Therapy; Rehabilitation; Aftercare; Continuity of Patient Care; Patient Care; Therapeutics; Physical Therapy Modalities

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assoc. Prof.

Study Record Dates

• First Submitted: July 1, 2026
• First Posted: July 8, 2026
• Study Start: February 1, 2026
• Primary Completion: May 1, 2026
• Study Completion: June 1, 2026
• Last Updated: July 8, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)