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

Study Overview
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Brief Summary
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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

Detailed Description
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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.

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

Conditions
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Heat-suit Endurance Training, Non-heat-suit Endurance Training

Intervention / Treatment
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* Behavioral: Heat-suit endurance training
* Behavioral: Non-heat-suit endurance training


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: The study will be conducted as a five-week intervention. In the heat-suit arm, participants will conduct a 50-minute low-intensity cycling session with heat suit five time a week. In the none-heat-suit arm, participants will conduct similar amounts of low-intensity cycling without heat suit. These training sessions will complement the habitual training of the participants. Participants will be allocated into the two arms in a planned randomized manner. In short, participants will be stratified based on baseline performance levels (VO2max), whereby they will be allocated into the two intervention arms in a manner that ensures similar average performance levels between the two arms.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Heat-suit training<br>Low-intensity endurance training with heat suit | Behavioral: Heat-suit endurance training<br>* 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<br>* Other names: Heat training;|
| Other: Non-heat-suit training<br>Low-intensity endurance training without heat suit | Behavioral: Non-heat-suit endurance training<br>* 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<br>* Other names: Control group;|

What is the study measuring?
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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) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Cycling, Heat, Hemoglobin mass, Skeletal muscle, Elite cyclists, Endurance performance, Mitochondria