The Galway Sea Swimmers Study (GS3)

The Galway Sea Swimmers Study: A Randomized Study of the Effect of Cold-Water Sea Swimming on Cardiovascular Risk Factors

Cardiovascular disease (CVD) is the leading cause of death worldwide. Hypertension is a well-established risk factor for the development of CVD. Lifestyle modifications, including exercise, remain the cornerstone of blood pressure (BP)-lowering strategy. Swimming has long been a popular recreational activity for exercise, and is recently gaining widespread recognition as an effective option in maintaining and improving cardiovascular health. Previous studies that involved pool swimming as an intervention (versus no pool swimming) demonstrated favorable benefits of the former on BP reduction. However, no studies to date have specifically investigated the effect of cold-water sea swimming on BP. Indeed, the naturally lower water temperature in the sea may engender a 'cold water immersion' experience in sea swimmers with subsequent stress physiology, which have been shown to exert unique effects on cardiovascular hemodynamics. This study primarily aims to determine the impact of cold-water sea swimming on BP in a group of habitual sea swimmers in Galway who will be randomly assigned to either continue or stop swimming for 4-6 weeks. Other objective and subjective health benefits to sea swimming will also be explored in this study. Given the ubiquitous nature of this activity in the Irish general public, particularly in Galway, this study has potential from a public health perspective, and would add to the literature base pertaining to the benefits of sea swimming on cardiovascular health.

Study Overview

• Status: Suspended
• Conditions: Cardiovascular Diseases; Hypertension
• Intervention / Treatment: Other: No cold-water sea swimming; Other: Cold-water sea swimming

Detailed Description

Consenting participants will be randomly assigned, 1:1, to either continuation of sea swimming or discontinuation of sea swimming for 4-6 weeks, stratified by the type of swimmer (those who purely immerse in the water for a brief period of time versus those who actually swim [i.e., exercise] in the water) and use of blood pressure medication at the time of study commencement (yes or no), using a block size of four to maintain balance between intervention arms. In line with previous studies that assessed the impact of swimming intervention on BP, participants randomized to the swimming arm should pursue sea swimming 2 or more days/week.

• Study Type: Interventional
• Enrollment (Anticipated): 150
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Ireland
  • Galway, Ireland, H91 FF68
    • Croi Heart and Stroke Centre

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years to 96 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• habitual swimmers (i.e., sea swimming at least 2 times/week for the past year)
• 18 years of age or older
• able to provide informed consent

Exclusion Criteria:

• underlying cardiac (e.g., self-reported heart failure) or pulmonary diseases (e.g., self-reported chronic obstructive pulmonary disease)
• recent orthopedic procedures (e.g., joint replacement therapy)
• severe disabling comorbidity
• recent arm (both arms) or chest wall injury
• pregnant or breast feeding

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: No sea swimming; Stop sea swimming for 4-6 weeks	Other: No cold-water sea swimming; Discontinue sea swimming for 4-6 weeks
Active Comparator: Sea swimming; Continue sea swimming for 4-6 weeks	Other: Cold-water sea swimming; Continue sea swimming for 4-6 weeks

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in mean systolic blood pressure	Systolic blood pressure recorded using a 24-hour ambulatory blood pressure monitor	Measured at baseline and again at 6 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Pulse Wave Velocity	Pulse wave velocity measured using Complior Device	Measured at baseline and 6 weeks
Change in Augmentation index	Augmentation index measured using Complior device	Measured at baseline and 6 weeks
Change in Heart rate variability	Measured using 24-hour ambulatory blood pressure monitor	Measured at baseline and 6 weeks
Change in Health-related quality of life	Measure using EQ-VAS (visual analog scale) instrument. Values between 0 (worst imaginable health) and 100 (best imaginable health)	Administered at baseline and 6 weeks
Change in mean diastolic blood pressure	Diastolic blood pressure recorded using a 24-hour ambulatory blood pressure monitor	Measured at baseline and again at 6 weeks

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Sleep quality	Measured using Pittsburgh Sleep Quality Index. Values between 0 and 21, higher score indicates worse sleep quality	Administered at baseline and 6 weeks
Change in Muscular strength	Measured using Hand grip dynamometer	Measured at baseline and 6 weeks

Collaborators and Investigators

• Sponsor: National University of Ireland, Galway, Ireland
• Investigators: Principal Investigator: John William McEvoy, MBBCh MHS, National University of Ireland, Galway

Study record dates

Study Major Dates

• Study Start (Anticipated): October 1, 2020
• Primary Completion (Anticipated): July 1, 2021
• Study Completion (Anticipated): October 1, 2021

Study Registration Dates

• First Submitted: February 24, 2020
• First Submitted That Met QC Criteria: February 26, 2020
• First Posted (Actual): March 2, 2020

Study Record Updates

• Last Update Posted (Actual): June 30, 2020
• Last Update Submitted That Met QC Criteria: June 26, 2020
• Last Verified: April 1, 2020

More Information

Terms related to this study

• Keywords: Exercise; Cardiovascular Diseases; Hypertension; Heart Rate Variability; Blood Pressure; Cardiac Disease; Health-Related Quality Of Life; Heart Diseases; Vascular Stiffness; Pulse Wave Analysis; Swimming; Immersion
• Additional Relevant MeSH Terms: Vascular Diseases; Hypertension; Cardiovascular Diseases
• Other Study ID Numbers: C.A. 2327

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No