We recently looked on our site at the best time to train and so a recent study from researchers in Brazil (1) exploring the impact of caffeine on morning performance piqued our interest.
The study was designed to investigate whether caffeine ingestion can counteract the morning reduction in neuromuscular performance associated with the circadian rhythm pattern.
Twelve experienced weight trained men performed a battery of neuromuscular tests under three different conditions; a) morning at 10AM with caffeine ingestion dosed at 3mg/kg (AMCAF), b) morning with a placebo (AMPLA), and afternoon at 6PM with placebo (PMPLA). A randomised, double blind crossover design was used to limit the potential for error and bias from affecting the results. Subjects were tested on the velocity of movement during full squats (SQ) and Bench Presses (BP) using loads that were aimed to test maximum strength and muscle power. In addition, serum testosterone, cortisol and growth hormone levels were taken at the start of each trial while, in addition, levels of endogenous catecholamines were measured before and after the trail following a bout of six reps of squats.
Dynamic muscle strength and power was significantly better in the PM group compared to AMPLA (3.0%–7.5%; p≤0.05). During the AMCAF trial performance increased above AMPLAC levels (4.6%–5.7%; p≤0.05) with the exception of bench press velocity. During the AMCAF trial sympathetic nervous system activation was increased above the level of the AMPLAC trial. Levels of testosterone and cortisol were higher during the morning trials while growth hormone output was greater in the afternoon trial.
The researchers concluded that caffeine intake reverses the morning neuromuscular declines in resistance trained men, raising performance to the levels of the afternoon trial. Electrical muscle stimulation data along with norepinephrine levels suggested caffeine works to increasese performance through heightening the activity of the central nervous system.
Previous research has shown that training in the morning is associated with poorer performance (2, 3) and that this effect is observed across a number of motor tasks including various athletic activities. To date there has been no categorical answer explaining the basis for this impaired performance with body temperature, blood hormone status and sympathetic nervous activity all proposed, as well as possible impaired muscle performance via inhibited phosphagen uptake and muscle buffering capacity.
While some research had established that increasing body heat can help to ameliorate the loss in performance associated with morning training (4, 5, 6), in none of these studies did performance reach levels achieved in the afternoon.
The use of caffeine, a common ingredient in virtually all pre-workout supplements, is supported by an abundance of research showing its ability to enhance both endurance and strength (7,8) but this is the first study we have seen which tested its ability to reverse the normal circadian rhythm. The results reported are impressive with the study itself monitoring and screening participants rigorously to ensure that subjects both had previous extensive weight training experience but also adhered to a controlled dietary protocol, both in the day prior and during the three days of the test to eliminate possible interference from previous use of stimulants or the effects of food. The amount of caffeine used was a reasonable level found in pre-workouts and equates to around 2.5 cups of black coffee. The average performance increase seen of 3-6% is enough to bring morning performance up to evening levels. Whether caffeine could raise evening performance by 3-6% if used at that time was not looked at but, as evidenced by real world feedback and trials such as that involving the preworkout NO Shotgun, it is quite likely it could do.
It is worth mentioning that the results observed for blood hormone levels is consistent with prior research. Despite the fact that testosterone was higher in the morning, the testosterone to cortisol ratio was higher in the afternoon session, which would be conducive for enhancing performance and muscle building results.
In conclusion, we would say that this study should be something to take into account if training in the morning either by habit or necessity, with the use of caffeine, and likely other popular pre-workout stimulants, an effective aid to raising performance for athletes.
Author: Reggie Johal
1. Ricardo Mora-Rodríguez, Jesus García Pallarés, Álvaro López-Samanes, Juan Fernando Ortega, and Valentín E. Fernández-Elías (2012): Caffeine Ingestion Reverses the Circadian Rhythm Effects on Neuromuscular Performance in Highly Resistance-Trained Men
2. Sedliak M, Finni T, Cheng S, Haikarainen T, Häkkinen K. Diurnal variation in maximal and submaximal strength, power and neural activation of leg extensors in men: multiple sampling across two consecutive days. Int J Sports Med. 2008;29(3):217–24.
3. Hayes L, Bickerstaff G, Baker JS. Interactions of cortisol, testosterone, and resistance training: influence of circadian rhythms. Chronobiol Int. 2010;27(4):675–705.
4. Racinais S, Blonc S, Jonville S, Hue O. Time of day influences the environmental effects on muscle force and contractility. Med Sci Sports Exerc. 2005;37(2):256–61.
5. Racinais S, Blonc S, Hue O. Effects of active warm-up and diurnal increase in temperature on muscular power. Med Sci Sports Exerc. 2005;37(12):2134–9.
6. Taylor KJ, Cronin B, Gill N, Chapman DW, Sheppard JM. Warm-up affects diurnal variation in power output. Int J Sports Med. 2011;32(3):185–9.
7. Warren GL, Park ND, Maresca RD, McKibans KI, Millard-Stafford ML. Effect of caffeine ingestion on muscular strength and endurance: a meta-analysis. Med Sci Sports Exerc. 2010;42(7):1375–87.
© 2012, Reggie Johal. All rights reserved.