Heat-suit Endurance Training, Non-heat-suit Endurance Training
Conditions
Keywords
Cycling, Heat, Hemoglobin mass, Skeletal muscle, Elite cyclists, Endurance performance, Mitochondria
Brief summary
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
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.
Interventions
BEHAVIORALNon-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
BEHAVIORALHeat-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
Sponsors
Inland Norway University of Applied Sciences
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Intervention 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.
Eligibility
Sex/Gender
ALL
Age
18 Years to 45 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Hemoglobin mass | Changes from before the intervention (T0) to immediately after the intervention (T1) | Hemoglobin mass measured using CO rebreathing (g) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Maximal oxygen consumption | Changes from before the intervention (T0) to immediately after the intervention (T1) | Maximal oxygen consumption measured during an incremental cycling exercise test to exhaustion |
| Maximal aerobic power output | 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 |
| Power output at lactate threshold | 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) |
| Gross efficiency | 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 |
| Fractional utilization of VO2max (incremental test) | 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) |
| Fractional utilization of VO2max (15-minute performance test) | Changes from before the intervention (T0) to immediately after the intervention (T1) | Fractional utilization of VO2max measured during a 15-minute performance test |
| Sprint performance | Changes from before the intervention (T0) to immediately after the intervention (T1) | Mean power output measured during a 10-second all-out cycling sprint |
| Performance during a 15-minute all-out cycling test | Changes from before the intervention (T0) to immediately after the intervention (T1) | Mean power output measured during a 15-minute all-out cycling test |
| Performance during a 40-minute all-out cycling test | Changes from before the intervention (T0) to immediately after the intervention (T1) | Mean power output measured during a 40-minute all-out cycling test |
| Maximal concentric force production | Changes from before the intervention (T0) to immediately after the intervention (T1) | Maximal concentric force production measured using a seated leg press test |
| Hematocrit | Changes from before the intervention (T0) to immediately after the intervention (T1) | Hematocrit measured using centrifugation |
| Hemoglobin mass | Changes from immediately after the intervention (T1) to one month after the intervention (T2) | Hemoglobin mass measured using CO rebreathing (g) |
| Gene expression in skeletal muscle | 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) |
| Mitochondrial respiration in skeletal muscle | Immediately after the intervention (T1) | The ability of muscle mitochondria (extracted from homogenate; m. vastus lateralis) to consume oxygen in vitro |
| Mitochondrial content in skeletal muscle | Immediately after the intervention (T1) | Mitochondria content in m. vastus lateralis measured using electron microscopy |
| Total RNA content in skeletal muscle | 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 |
| Blood volume | Changes from before the intervention (T0) to immediately after the intervention (T1) | Blood volume measured using CO rebreathing |
| Plasma volume | Changes from before the intervention (T0) to immediately after the intervention (T1) | Plasma volume measured using CO rebreathing |
| Red blood cell volume | Changes from before the intervention (T0) to immediately after the intervention (T1) | Red blood cell volume measured using CO rebreathing |
Other
| Measure | Time frame | Description |
|---|---|---|
| Training volume | Throughout study completion (daily), an average of five weeks | Self-reported training volume measured as time-spent in different exercise intensity zones |
| Iron intake | Throughout study completion (daily), an average of five weeks | Self-reported intake of iron supplements |
Countries
Norway
Outcome results
None listed