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Completed

NCT Number: NCT04611646

Effects of Heat-suit Training on Biological and Performance Characteristics 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

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Key information

Conditions

Heat-suit Endurance Training Non-heat-suit Endurance Training

Age range

18 year–45 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Inland Norway University of Applied Sciences

Lillehammer, Inland Norway, 2613, Norway

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Heat-suit endurance training

Behavioral

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

Non-heat-suit endurance training

Behavioral

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

Primary outcomes

  1. Hemoglobin mass

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    Hemoglobin mass measured using CO rebreathing (g)

Secondary outcomes

  1. Maximal oxygen consumption

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    Maximal oxygen consumption measured during an incremental cycling exercise test to exhaustion

  2. Maximal aerobic power output

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    Maximal aerobic power output measured as mean power output during the last minute of an incremental cycling exercise test to exhaustion

  3. Power output at lactate threshold

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    Power output at 4 mmol blood lactate concentration measured during an incremental cycling exercise test (with 5 minute steps)

  4. Gross efficiency

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    Contribution of total energy turnover to power output in the fresh and fatigued state

  5. Fractional utilization of VO2max (incremental test)

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    Fractional utilization of VO2max measured at 4 mmol blood lactate concentrations measured during an incremental cycling exercise test (with 5 minute steps)

  6. Fractional utilization of VO2max (15-minute performance test)

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    Fractional utilization of VO2max measured during a 15-minute performance test

  7. Sprint performance

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    Mean power output measured during a 10-second all-out cycling sprint

  8. Performance during a 15-minute all-out cycling test

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    Mean power output measured during a 15-minute all-out cycling test

  9. Performance during a 40-minute all-out cycling test

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    Mean power output measured during a 40-minute all-out cycling test

  10. Maximal concentric force production

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    Maximal concentric force production measured using a seated leg press test

  11. Gene expression in skeletal muscle

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    RNA abundances in m. vastus lateralis measured using qPCR (e.g. messenger RNA and ribosomal RNA)

  12. Mitochondrial respiration in skeletal muscle

    Time frame: Immediately after the intervention (T1)

    The ability of muscle mitochondria (extracted from homogenate; m. vastus lateralis) to consume oxygen in vitro

  13. Mitochondrial content in skeletal muscle

    Time frame: Immediately after the intervention (T1)

    Mitochondria content in m. vastus lateralis measured using electron microscopy

  14. Total RNA content in skeletal muscle

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    Total RNA content in m. vastus lateralis (per unit tissue weight) measured using spectrophotometry

  15. Blood volume

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    Blood volume measured using CO rebreathing

  16. Plasma volume

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    Plasma volume measured using CO rebreathing

  17. Red blood cell volume

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    Red blood cell volume measured using CO rebreathing

  18. Hematocrit

    Time frame: Changes from before the intervention (T0) to immediately after the intervention (T1)

    Hematocrit measured using centrifugation

  19. Hemoglobin mass

    Time frame: Changes from immediately after the intervention (T1) to one month after the intervention (T2)

    Hemoglobin mass measured using CO rebreathing (g)

  20. Blood volume

    Time frame: Changes from immediately after the intervention (T1) to one month after the intervention (T2)

    Blood volume measured using CO rebreathing

  21. Plasma volume

    Time frame: Changes from immediately after the intervention (T1) to one month after the intervention (T2)

    Plasma volume measured using CO rebreathing

  22. Red blood cell volume

    Time frame: Changes from immediately after the intervention (T1) to one month after the intervention (T2)

    Red blood cell volume measured using CO rebreathing

  23. Hematocrit

    Time frame: Changes from immediately after the intervention (T1) to one month after the intervention (T2)

    Hematocrit measured using centrifugation

Other outcomes

  1. Training volume

    Time frame: Throughout study completion (daily), an average of five weeks

    Self-reported training volume measured as time-spent in different exercise intensity zones

  2. Iron intake

    Time frame: Throughout study completion (daily), an average of five weeks

    Self-reported intake of iron supplements

Sponsors and collaborators

Lead sponsor

Inland Norway University of Applied Sciences

Other

Registry information

Official study title

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

Acronym: HeatME

Important dates

Study start
2020
Primary completion
2020
Study completion
2020
First posted
Nov 2, 2020
Registry last updated
Mar 1, 2021

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.