Caffeine and Exercise

1. Caffeine and Exercise Steve Bui June 27th, 2012

2. NCAA and IOC placed caffeine as a “regulated” substance • IOC: 12µg/ml • NCAA: 15µg/ml • Approximately 9+mg/kg of caffeine • ~100mg of caffeine = 1.5µg/ml • ~100-150mg caffeine in 1 cup of coffee • Example: 175 lbs male • 175lbs = 79.5 kg • 715mg caffeine (7 cups +) at 9mg/kg

3. What is Caffeine? • Caffeine is a 1,3,7-trimethylxanthine • Xanthine molecule with methyl groups replacing all of the three hydrogens

4. Metabolized in the liver by Cytochrome P450 (CYP1A2) • Approximate half-life is 5 hours (adult) • Theophylline: Muscle relaxant • Theobromine: Diuretic

5. Where is it coming from?

7. Endurance Exercise • Study 1 • Study: Bell et al. 2002 • 21 individuals • Regularly active in aerobic activities • Cycleergometer with increasing power output until exhaustion • 6mg/kg of body weight • Found significance differences in non-users & 1, 3 hour users

8. Study 2 • Hogervorst et al. 2006 • Supplement given at 0hrs, 55mins, 115mins • Supplement for Caf: 100mg, CHO: protein (5.4g), carb (44.9g), fat (3.2g) Time till exhaustion test done after 150 minute V02 60% • 751 sec 84% improvement with normal beverage • 397 sec 44% better than just CHO alone

9. Study 3 • O’Rouke et. al (2007) • 15 well trained, 15 recreationally trained males • 5km run, 5mg/kg caffeine • Rec 1.0% faster placebo • Trained  1.1% faster than placebo • 27/30 runners gained a performance benefit • Times of completion: • Trained: 1058 ± 68 s versus 1047 ± 69 s (~17mins) • Rec trained: 1298 ± 84s versus 1286 ± 86s (~21mins)

10. Study 4 • Backhouse et al. (2011) • 12 endurance trained athletes • 6mg/kg after overnight fast • Perceived exertion scale Significant differences seen between two groups

11. Summary of Endurance • Time to exhaustion has increased • Rate of perceived exertion has decreased • Decreased times with distance running • Caffeine more effective than carb supplement • Total work has also been shown to increase (Ivey et al. 1979)

12. Strength • Astorino et al. 2008 • 22 resistance trained men • 6mg/kg caffeine • 1RM Leg Press/Chest Press, To failure at 60% 1RM Leg Press/Chest press • Study 1 No significant different in 1RM or max reps at 60% 1RM Total weight was 11-12% higher in caffeine vs placebo but no signficance

13. Woolf et al 2008; Beck et al 2006 • 18 males/22males • 5mg/kg body weight • Leg Press + Chest Press • Study 2 Significant differences in chest press and peak power

14. Greem et al. 2007 • 17 individuals • Strength training history for minimum of 8 weeks • 6mg/kg Body Weight • 10 RM weight used • Study 3 Saw significance in 3rd set of leg press only

15. Study 3

16. Graham et al 2007 • Study 3

17. How does caffeine work? • Caffeine molecule similar in structure to adenosine • Works as a competitive inhibitor

18. What is Adenosine? • Adenosine • By product of ATP • Acts as a neurotransmitter • Not released from synapses • Slows down neural activity • Promotes sleep and suppresses arousal • Vasodialator

19. Adenosine Receptors • Four types: A1, A2A, A2B, A3 • Found in most tissues: brain, heart, smooth muscle, adipocytes, skeletal muscle • Generally causes activation or inhibition of AdenylateCyclase • Responsible for activation/inhibition of cAMP (2nd messenger system) • Adenosine inhibits neural activity • Caffeine increases neural activity

20. Increased Fat Oxidation? • Graham et al 2001 • 6mg/kg • 70% max oxygen uptake for an 1hour • Caffeine ingestion does not decreases respiratory exchange ratio (RER) • Free Fatty Acid net uptake was not enhanced with caffeine

21. Muscle Glycogen Sparing? • Graham et al 2008 • 6mg/kg • 70-85% max oxygen uptake • 10-15 minutes post exercise

22. Proposed Projects • Studies look at in performance only • How does caffeine affect post-resistance exercise?

23. The activation of AMPK • Increased AMP = Increased AMPK Actviation • AMPK is the “metabolic master switch” • Activation of AMPK increases cellular energy levels by inhibiting anabolic energy systems • Incubated with 3mmol/L of caffeine or 15 minutes at a time • Rat Soleus • Egawa et al. 2009; Jensen et. Al 2007

24. 6mg/kg BW • RE 8 exercises, 2 sets of 10 at 75% 1RM • Wu et al. 2010 • 5mg/kg BW caffeine • Keiser equipment, chest, leg to failure. 30 sec wingate. • Woolf et al. 2008

25. Potential Caffeine Effects • Additionally, caffeine has been shown to potentially inhibit: • Akt • mTOR • Phosphoinositide-3-Kinase (PI3K)

26. Scott et al. 1998 • Incubated with 5mM theophylline

27. Foukas et al. 2002

28. Animal Model • 48 Male Sprague-Dawley Rats (6 months) • Six groups: • No exercise no caffeine • Exercise no caffeine • No exercise low caffeine • Exercise low caffeine • No exercise high caffeine • Exercise high caffeine • Low caffeine: 3mg/kg; High Caffeine 6mg/kg • Exercise will take place in the form of a rat squat box • Day 1: 30/80/130/180/230 14/12/10/8/6 • Day 2:80/80/130/180/230 16/16/10/10/8 • Day 3/4:80/130/180/180/230 – 18/16/14/8 • Deuterium Oxide as protein tracer • Look at Protein Fraction Synthesis Rates

30. Human Model • 24 trained individuals • Males, ages 20-26 • Uni-lateral one-legged exercise • Participants placed in 2 groups • Caffeine • Placebo • 5 sets of leg press and leg extension till failure 80% 1RM • 24 hour post-exercise muscle biopsy • Use of deuterium oxide as a protein tracer • Look at Protein Fraction Synthesis Rates