Effects of Heat-suit Training on Biological and Performance Characteristics in Elite Cyclists (HeatME)

Effects of Heat-suit Training on Training-associated Changes in Hemoglobin Mass, Muscle Characteristics and Endurance Performance in Elite Cyclists

The overall objective of the study is to investigate the effects of five weeks of heat-suit training on training-associated changes in hemoglobin mass, skeletal muscle characteristics and endurance exercise performance in elite cyclists

Study Overview

• Status: Completed
• Conditions: Heat-suit Endurance Training; Non-heat-suit Endurance Training
• Intervention / Treatment: Behavioral: Heat-suit endurance training; Behavioral: Non-heat-suit endurance training

Detailed Description

Endurance exercise performance depends on a range of determinants, including hemoglobin mass in blood and content of respiratory mitochondria in skeletal muscle. Low-intensity training (LIT) with heat exposure may be beneficial for development of these variables. The purpose of this study is to investigate the effects of five weeks of LIT-training with heat suit (five times a week; 50 min per session) on hemoglobin mass and other blood characteristics in elite cyclists (males and females) compared to a non-heat-suit training control group, including subsequent investigation of the retrograde effects of ~one month of training without heat suit. The study will also investigate the effects of heat-suit training on endurance exercise performance/performance determinants and other muscle biological charateristics, and will investigate the basic characteristics of mitochondrial function and abundances in these highly trained athletes. Training sessions with heat suit (or lack thereof) will complement the habitual training routines of the participants.

• Study Type: Interventional
• Enrollment (Actual): 53
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Norway
  • Inland Norway
    • Lillehammer, Inland Norway, Norway, 2613
      • Inland Norway University of Applied Sciences

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 45 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• VO2max > 65 ml/kg/min (male participants)
• VO2max > 50 ml/kg/min (female participants)
• >7 hours of endurance training per week for the 6 months leading up to the study

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: Heat-suit training; Low-intensity endurance training with heat suit	Behavioral: Heat-suit endurance training; Participants (elite cyclists) will conduct five 50-minute low-intensity cycling sessions with heat suit per week for five weeks. These sessions will complement their habitual training routines, which will consist of endurance training with intensities at or below lactate threshold. Participants will ingest 100 mg Fe2+ on a daily basis to support de novo synthesis of hemoglobin; Other Names: Heat training
Other: Non-heat-suit training; Low-intensity endurance training without heat suit	Behavioral: Non-heat-suit endurance training; Participants (elite cyclists) will conduct low-intensity cycling without heat suit for five weeks (volume- and intensity-matched to the heat-suit arm). Participants will ingest 100 mg Fe2+ on a daily basis to support de novo synthesis of hemoglobin; Other Names: Control group

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hemoglobin mass	Hemoglobin mass measured using CO rebreathing (g)	Changes from before the intervention (T0) to immediately after the intervention (T1)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximal oxygen consumption	Maximal oxygen consumption measured during an incremental cycling exercise test to exhaustion	Changes from before the intervention (T0) to immediately after the intervention (T1)
Maximal aerobic power output	Maximal aerobic power output measured as mean power output during the last minute of an incremental cycling exercise test to exhaustion	Changes from before the intervention (T0) to immediately after the intervention (T1)
Power output at lactate threshold	Power output at 4 mmol blood lactate concentration measured during an incremental cycling exercise test (with 5 minute steps)	Changes from before the intervention (T0) to immediately after the intervention (T1)
Gross efficiency	Contribution of total energy turnover to power output in the fresh and fatigued state	Changes from before the intervention (T0) to immediately after the intervention (T1)
Fractional utilization of VO2max (incremental test)	Fractional utilization of VO2max measured at 4 mmol blood lactate concentrations measured during an incremental cycling exercise test (with 5 minute steps)	Changes from before the intervention (T0) to immediately after the intervention (T1)
Fractional utilization of VO2max (15-minute performance test)	Fractional utilization of VO2max measured during a 15-minute performance test	Changes from before the intervention (T0) to immediately after the intervention (T1)
Sprint performance	Mean power output measured during a 10-second all-out cycling sprint	Changes from before the intervention (T0) to immediately after the intervention (T1)
Performance during a 15-minute all-out cycling test	Mean power output measured during a 15-minute all-out cycling test	Changes from before the intervention (T0) to immediately after the intervention (T1)
Performance during a 40-minute all-out cycling test	Mean power output measured during a 40-minute all-out cycling test	Changes from before the intervention (T0) to immediately after the intervention (T1)
Maximal concentric force production	Maximal concentric force production measured using a seated leg press test	Changes from before the intervention (T0) to immediately after the intervention (T1)
Gene expression in skeletal muscle	RNA abundances in m. vastus lateralis measured using qPCR (e.g. messenger RNA and ribosomal RNA)	Changes from before the intervention (T0) to immediately after the intervention (T1)
Mitochondrial respiration in skeletal muscle	The ability of muscle mitochondria (extracted from homogenate; m. vastus lateralis) to consume oxygen in vitro	Immediately after the intervention (T1)
Mitochondrial content in skeletal muscle	Mitochondria content in m. vastus lateralis measured using electron microscopy	Immediately after the intervention (T1)
Total RNA content in skeletal muscle	Total RNA content in m. vastus lateralis (per unit tissue weight) measured using spectrophotometry	Changes from before the intervention (T0) to immediately after the intervention (T1)
Blood volume	Blood volume measured using CO rebreathing	Changes from before the intervention (T0) to immediately after the intervention (T1)
Plasma volume	Plasma volume measured using CO rebreathing	Changes from before the intervention (T0) to immediately after the intervention (T1)
Red blood cell volume	Red blood cell volume measured using CO rebreathing	Changes from before the intervention (T0) to immediately after the intervention (T1)
Hematocrit	Hematocrit measured using centrifugation	Changes from before the intervention (T0) to immediately after the intervention (T1)
Hemoglobin mass	Hemoglobin mass measured using CO rebreathing (g)	Changes from immediately after the intervention (T1) to one month after the intervention (T2)
Blood volume	Blood volume measured using CO rebreathing	Changes from immediately after the intervention (T1) to one month after the intervention (T2)
Plasma volume	Plasma volume measured using CO rebreathing	Changes from immediately after the intervention (T1) to one month after the intervention (T2)
Red blood cell volume	Red blood cell volume measured using CO rebreathing	Changes from immediately after the intervention (T1) to one month after the intervention (T2)
Hematocrit	Hematocrit measured using centrifugation	Changes from immediately after the intervention (T1) to one month after the intervention (T2)

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Training volume	Self-reported training volume measured as time-spent in different exercise intensity zones	Throughout study completion (daily), an average of five weeks
Iron intake	Self-reported intake of iron supplements	Throughout study completion (daily), an average of five weeks

Collaborators and Investigators

• Sponsor: Inland Norway University of Applied Sciences

Study record dates

Study Major Dates

• Study Start (Actual): October 19, 2020
• Primary Completion (Actual): December 13, 2020
• Study Completion (Actual): December 13, 2020

Study Registration Dates

• First Submitted: October 20, 2020
• First Submitted That Met QC Criteria: October 27, 2020
• First Posted (Actual): November 2, 2020

Study Record Updates

• Last Update Posted (Actual): March 1, 2021
• Last Update Submitted That Met QC Criteria: February 26, 2021
• Last Verified: November 1, 2020

More Information

Terms related to this study

• Keywords: Cycling; Heat; Mitochondria; Skeletal muscle; Endurance performance; Hemoglobin mass; Elite cyclists
• Other Study ID Numbers: Trainome 2020#025

Drug and device information, study documents

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