Condition
Warm- or Hot-Weather Exercise Performance
Exercising in the heat forces your body to work harder to cool itself while also powering the workout, which can blunt performance and, in severe cases, lead to heat illness. The evidence is strongest for electrolytes and carbohydrates, which replace minerals lost in sweat and fuel long efforts. Small trials of quercetin, betaine and tyrosine, with 10 to 31 people, found no clear difference in performance measures.
Sources: PMID 21558570
- Supplements studied
- 5
- Graded outcomes
- 5
- Trials
- 14
- People studied
- 327
Evidence by supplement
- Strong
- Moderate
- Limited
- Very limited
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Aldosterone Moderate Increase | Improves (the measure goes up) | Moderate effect | 20 people | |||
| Blood Pressure No effect | NoneNo effect | 44 people | ||||
| Power Output | Improves (the measure goes up) | 44 studies | 20 people | |||
Studies that measured power output
| ||||||
| Muscle Creatine Content | Improves (the measure goes up) | 11 studies | 21 people | |||
Studies that measured muscle creatine content
| ||||||
| Weight | Changes; see studies | 10 studies | 20 people | |||
Studies that measured weight | ||||||
| Hydration (Total Body Water) | Improves (the measure goes up) | 5 studies | 221 people | |||
| Creatinine | Improves (the measure goes up) | 3 studies | 20 people | |||
| Heart Rate | Changes; see studies | 1 study | 20 people | |||
| Sprint Performance Metrics | Improves (the measure goes up) | 1 study | 20 people | |||
| Fatigue Resistance | Changes; see studies | 21 people | ||||
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anaerobic Capacity No effect | NoneNo effect | 1 study | 10 people | |||
Studies that measured anaerobic capacity | ||||||
| Exercise-induced Stress Response | Changes; see studies | 1 study | 8 people | |||
Studies that measured exercise-induced stress response | ||||||
| Rating of Perceived Exertion | Improves (the measure goes up) | 1 study | 10 people | |||
Studies that measured rating of perceived exertion | ||||||
| Hydration (Total Body Water) | Improves (the measure goes up) | 10 people | ||||
| Intestinal Permeability | Improves (the measure goes up) | 8 people | ||||
| Training Volume | Improves (the measure goes up) | 10 people | ||||
L-Tyrosine
- Aerobic Exercise Metrics
- Heart Rate: changes; see studies
- Rating of Perceived Exertion: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Aerobic Exercise Metrics No effect | NoneNo effect | 31 people | ||||
| Heart Rate | Changes; see studies | 5 studies | 31 people | |||
| Rating of Perceived Exertion | Improves (the measure goes up) | 3 studies | 23 people | |||
| Alertness | Improves (the measure goes up) | 1 study | 8 people | |||
| Blood glucose | Changes; see studies | 1 study | 8 people | |||
Studies that measured blood glucose | ||||||
| Body Temperature | Improves (the measure goes up) | 1 study | 16 people | |||
| Blood Lactate (Exercise) | Changes; see studies | 8 people | ||||
| Power Output | Improves (the measure goes up) | 15 people | ||||
| Vigor/Activity | Improves (the measure goes up) | 8 people | ||||
| Weight | Changes; see studies | 7 people | ||||
Betaine
- Anaerobic Capacity
- Oxygen Uptake: improves
- Blood glucose: changes; see studies
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anaerobic Capacity No effect | NoneNo effect | 10 people | ||||
| Oxygen Uptake | Improves (the measure goes up) | 1 study | 10 people | |||
Studies that measured oxygen uptake | ||||||
| Blood glucose | Changes; see studies | 10 people | ||||
| Heart Rate | Changes; see studies | 10 people | ||||
| Hematocrit | Improves (the measure goes up) | 10 people | ||||
| Hydration (Total Body Water) | Improves (the measure goes up) | 10 people | ||||
| Rating of Perceived Exertion | Improves (the measure goes up) | 10 people | ||||
Caffeine
- Adrenaline: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Adrenaline | Improves (the measure goes up) | 2 studies | 8 people | |||
Key findings
- AldosteroneImproves (the measure goes up)
- Anaerobic Capacity
- Blood Pressure
The Hot Weather Exercise Performance Support protocol
2 primary supplements · 7 supporting supplements
- Electrolytes (Sodium, Potassium, Magnesium)300–1,000 mg sodium per hour during prolonged hot weather exercise; potassium and magnesium as needed
- Glycerol1–1.5 g/kg body weight with fluid 60–120 min before exercise
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Studies cited
100 studies from PubMed
- Does creatine supplementation improve glycemic control and insulin resistance in healthy and diabetic patients? A systematic review and meta-analysis.
- Quercetin and Exercise Performance: A Meta-Analysis
- Quercetin and Blood Pressure: A Meta-Analysis of Randomized Trials
- Quercetin and Upper Respiratory Tract Infections: A Review
- Quercetin and Metabolic Syndrome: A Comprehensive Review
- Quercetin and Cardiovascular Health: A Systematic Review and Meta-Analysis
- Quercetin and Allergic Diseases: A Systematic Review
- Bioavailability and Safety of Quercetin: A Review
- Quercetin and Lipid Profile: A Meta-Analysis
- Quercetin and Inflammation: A Systematic Review
- Quercetin and Antioxidant Activity: Mechanisms and Clinical Evidence
- Role of creatine supplementation on exercise-induced cardiovascular function and oxidative stress
- Three weeks of creatine monohydrate supplementation affects dihydrotestosterone to testosterone ratio in college-aged rugby players
- Does creatine supplementation improve the plasma lipid profile in healthy male subjects undergoing aerobic training
- Effects of creatine supplementation on glucose tolerance and insulin sensitivity in sedentary healthy males undergoing aerobic training
- Creatine supplementation increases glycogen storage but not GLUT-4 expression in human skeletal muscle
- Creatine supplementation affects glucose homeostasis but not insulin secretion in humans
- Creatine supplementation and health variables: a retrospective study
- Effect of oral creatine supplementation on human muscle GLUT4 protein content after immobilization
- Role of submaximal exercise in promoting creatine and glycogen accumulation in human skeletal muscle
- Effects of L-tyrosine and carbohydrate ingestion on endurance exercise performance
- Long-term effect of betaine on risk factors associated with the metabolic syndrome in healthy subjects
- The effect of low doses of betaine on plasma homocysteine in healthy volunteers
- Betaine, a promising new agent for patients with nonalcoholic steatohepatitis: results of a pilot study
- Influence of betaine consumption on strenuous running and sprinting in a hot environment
- Effect of betaine supplementation on cycling sprint performance
- Betaine supplementation enhances anabolic endocrine and Akt signaling in response to acute bouts of exercise
- Effect of betaine supplementation on power performance and fatigue
- Effect of 15 days of betaine ingestion on concentric and eccentric force outputs during isokinetic exercise
- Creatine but not betaine supplementation increases muscle phosphorylcreatine content and strength performance
- The effects of chronic betaine supplementation on exercise performance, skeletal muscle oxygen saturation and associated biochemical parameters in resistance trained men
- Ergogenic effects of betaine supplementation on strength and power performance
- Betaine supplementation lowers plasma homocysteine in healthy men and women
- Betaine supplementation decreases plasma homocysteine concentrations but does not affect body weight, body composition, or resting energy expenditure in human subjects
- Orally administered betaine has an acute and dose-dependent effect on serum betaine and plasma homocysteine concentrations in healthy humans
- Betaine supplementation and plasma homocysteine in healthy volunteers
- Dietary and supplementary betaine: effects on betaine and homocysteine concentrations in males
- Betaine for nonalcoholic fatty liver disease: results of a randomized placebo-controlled trial
- Evaluation of the clinical efficacy of a betaine-containing mouthwash and an intraoral device for the treatment of dry mouth
- Safety and effectiveness of topical dry mouth products containing olive oil, betaine, and xylitol in reducing xerostomia for polypharmacy-induced dry mouth
- Betaine-containing toothpaste relieves subjective symptoms of dry mouth
- Effects of a betaine-containing toothpaste on subjective symptoms of dry mouth: a randomized clinical trial
- Effects of 1,3-dimethylamylamine and caffeine alone or in combination on heart rate and blood pressure in healthy men and women
- Ergogenic effect of varied doses of coffee-caffeine on maximal aerobic power of young African subjects
- The effect of caffeine ingestion on mood state and bench press performance to failure
- Effect of Caffeine on LT, VT and HRVT
- Metabolic effects of caffeine ingestion and physical work in 75-year old citizens. A randomized, double-blind, placebo-controlled, cross-over study
- Dose response effects of a caffeine-containing energy drink on muscle performance: a repeated measures design
- Acute caffeine ingestion increases voluntarily chosen resistance training load following limited sleep
- Effects of caffeine on the metabolic and catecholamine responses to exercise in 5 and 28 degrees C
- Caffeine ingestion reverses the circadian rhythm effects on neuromuscular performance in highly resistance-trained men
- Effect of two doses of caffeine on muscular function during isokinetic exercise
- Dose effect of caffeine on testosterone and cortisol responses to resistance exercise
- The effects of low-dose caffeine on perceived pain during a grip to exhaustion task
- Caffeine increases sweating sensitivity via changes in sudomotor activity during physical loading
- Effects of caffeinated and decaffeinated coffee on biological risk factors for type 2 diabetes: a randomized controlled trial
- Caffeine and sprinting performance: dose responses and efficacy
- Effects of caffeine on prolonged intermittent-sprint ability in team-sport athletes
- Caffeinated chewing gum increases repeated sprint performance and augments increases in testosterone in competitive cyclists
- The effects of different doses of caffeine on endurance cycling time trial performance
- Effect of caffeine ingestion on time trial performance in cyclists: a systematic review and meta-analysis.
- Effect of ambient temperature on caffeine ergogenicity during endurance exercise
- The influence of a CYP1A2 polymorphism on the ergogenic effects of caffeine
- Caffeine ingestion, affect and perceived exertion during prolonged cycling
- Effect of caffeine intake on pain perception during high-intensity exercise
- Caffeine as an analgesic adjuvant for acute pain in adults
- Caffeine for the prevention of injuries and errors in shift workers.
- Caffeine enhances working memory for extraverts
- Comparing the benefits of caffeine, naps and placebo on verbal, motor and perceptual memory
- Subjective, behavioral, and physiological effects of acute caffeine in light, nondependent caffeine users
- Effects of caffeine and glucose, alone and combined, on cognitive performance
- Effects of acute caffeine consumption following sleep loss on cognitive, physical, occupational and driving performance: A systematic review and meta-analysis.
- Effect of caffeine on reactive agility time when fresh and fatigued
- Effects of Nutritional Interventions on Accuracy and Reaction Time with Relevance to Mental Fatigue in Sporting, Military, and Aerospace Populations: A Systematic Review and Meta-Analysis.
- Effect of caffeine on target detection and rifle marksmanship
- Association of the anxiogenic and alerting effects of caffeine with ADORA2A and ADORA1 polymorphisms and habitual level of caffeine consumption
- Caffeine: a double-blind, placebo-controlled study of its thermogenic, metabolic, and cardiovascular effects in healthy volunteers
- Caffeine can decrease insulin sensitivity in humans
- Effects of caffeine on glucose tolerance: a placebo-controlled study
- Caffeine ingestion decreases glucose disposal during a hyperinsulinemic-euglycemic clamp in sedentary humans
- Caffeinated coffee does not acutely affect energy intake, appetite, or inflammation but prevents serum cortisol concentrations from falling in healthy men
- Influence of caffeine on perception of effort, metabolism and exercise performance following a high-fat meal
- Impact of acute caffeine ingestion on endothelial function in subjects with and without coronary artery disease
- Caffeine and opening the eyes have additive effects on resting arousal measures
- Effects of diurnal variation and caffeine consumption on Test of Variables of Attention (TOVA) performance in healthy young adults
- Caffeine supplementation and multiple sprint running performance
- Effects of caffeine on repeated sprint ability, reactive agility time, sleep and next day performance
- Genetic determinants of blood pressure responses to caffeine drinking
- Caffeine and Physiological Responses to Submaximal Exercise: A Meta-Analysis
- Wake up and smell the coffee: caffeine supplementation and exercise performance-an umbrella review of 21 published meta-analyses
- Effects of acute ingestion of caffeine on team sports performance: a systematic review and meta-analysis.
- Caffeine for asthma.
- The Effect of Consuming Caffeine Before Late Afternoon/Evening Training or Competition on Sleep: A Systematic Review with Meta-Analysis.
- The effect of caffeine on subsequent sleep: A systematic review and meta-analysis.
- The Prophylactic Effect of Acetaminophen and Caffeine on Post Dural Puncture Headache after Spinal Anesthesia for Cesarean Section: A Randomized Double-Blind Clinical Trial.
- The Effect of Pre-Exercise Caffeine and Glucose Ingestion on Endurance Capacity in Hypoxia: A Double-Blind Crossover Trial.
- Effect of creatine monohydrate in improving cellular energetics and muscle strength in ambulatory Duchenne muscular dystrophy patients: a randomized, placebo-controlled 31P MRS study
- Creatine for treating muscle disorders.
- Creatine monohydrate enhances strength and body composition in Duchenne muscular dystrophy
- Comparison of creatine ingestion and resistance training on energy expenditure and limb blood flow