Aerobic and Anaerobic Energy Pathways
Before we get into whether creatine and aerobic exercise/cardio are a good fit, we need to understand the basics of how the body produces ATP. ATP, or adenosine triphosphate, is the main energy currency in the body. Regardless of whether you eat fats, carbohydrates, or proteins, calories are eventually converted into ATP which directly powers muscle contractions. The body has a few ways to produce ATP depending on how demanding an activity is.
The body essentially has two choices when producing ATP: 1) anaerobic – creating a small amount of ATP very quickly, or, 2) aerobic – creating a large amount of ATP very slowly. Anaerobic energy pathways create enough ATP for short term needs: sprints, high intensity exercise, maximal lifts. This energy pathway does not need oxygen to operate but cannot be sustained over a long period of time. Creatine really shines in its ability to improve performance in anaerobic settings. It provides an additional pool of phosphate groups, allowing the body to quickly assemble more ATP.
For longer exercise bouts, the body uses an aerobic energy pathway; this requires oxygen. This pathway creates a lot more ATP, but requires more time. This pathway is ideal for long endurance activities such as running, swimming, rowing, biking, or less intensive sports. The question is whether creatine plays a significant role in this energy pathway.
Research on Creatine and Cardio
Study 1: Effects of creatine supplementation on muscle power, endurance, and sprint performance1
In the first study, researchers looked into whether creatine had an effect on endurance in handball players. Endurance was measured in a number of tests. In one test, subjects performed 10 continuous repetitions on the bench press, rested for 2 minutes, and attempted as many repetitions as possible. Subjects also performed a running test consisting of 40-20 meter sprints until exhaustion. In this study, subjects took a total of 20 grams of creatine monohydrate daily split in 4 doses.
The results showed improvements in total repetitions to fatigue on the bench press and squat but no improvement in the endurance running exercise.
Study 2: Combined Effect of Creatine Monohydrate or Creatine Hydrochloride and Caffeine Supplementation in Runners’ Performance and Body Composition2
This study looked at the effects creatine monohydrate and creatine hydrochloride, each combined with caffeine, had on running performance. The subjects were split into three groups: 1) creatine monohydrate + caffeine, 2) creatine hydrochloride + caffeine, 3) placebo + caffeine.
The creatine monohydrate group took 20 grams of creatine per day for 7 days followed by 5 grams of creatine for 21 days. The creatine hydrochloride group took 6 grams per day for 7 days followed by 1.5 grams per day for 21 days. All three groups ingested 2.7 mg of caffeine per pound of body weight.
All groups completed the same training protocol consisting of a pre-test, four weeks of supplementation combined with training designed to improve running performance, and a post test. Training included longer runs to increase endurance and shorter runs to improve speed. The pre and post running test was a 10 km timed run.
The results included a lot of observations. The rate of perceived exhaustion (a subjective measure of fatigue) was similar across all groups. Muscle soreness was significantly lower in the creatine monohydrate group than any of the other groups. Gastrointestinal discomfort perception was higher in the two creatine groups compared to the placebo group. The two creatine groups saw more weight gain than the placebo group. Between the two creatine groups, weight gain was similar.
In performance, the placebo group decreased their 10 km time from 56.4 minutes to 52.2 minutes. The creatine monohydrate group decreased their time from 59.7 minutes to 52.7 minutes. The creatine hydrochloride group decreased their time from 56.4 minutes to 51.2 minutes. In percentage terms, the decrease was: placebo -7.4%, creatine monohydrate -11.7%, creatine hydrochloride -9.2%. Both creatine groups saw a bigger decrease from pre to post testing than the placebo group.
Study 3: Ergolytic/Ergogenic Effects of Creatine on Aerobic Power3
This study looked at the effects of creatine on running performance. Researchers decided on using creatine citrate because it is more soluble than creatine monohydrate, is bonded to citric acid which may boost endurance activities such as running, and may delay neuromuscular fatigue.
Subjects took 20 grams of creatine citrate, divided into 4 equal doses daily for 5 days. They were tested on a treadmill to determine VO2 max and time to exhaustion before and after supplementation.
Results showed: 1) there was no improvement in endurance performance after creatine citrate supplementation, 2) creatine did not hurt endurance performance as some previous studies suggested, 3) body weight values increased significantly after supplementation.
The Bottom Line – Does creatine do anything for cardio, aerobic, or endurance activities?
The Good. In the first study, the creatine group saw an increase in performance on a repetitions to fatigue test. The second study saw increased running performance in both creatine groups. Additionally, the creatine monohydrate group saw decreased muscle soreness. The third study did not find that creatine harmed aerobic performance.
The Bad. The first study did not find creatine improved running performance. The third study also did not find creatine improved performance on a treadmill test. Some of the research also indicates creatine significantly increases body weight and gastrointestinal discomfort.
Recommendations for Creatine and Cardio
There are fundamental problems with supplementing creatine in order to improve aerobic performance. While creatine definitely helps improve anaerobic performance, there is much less evidence to suggest it does the same in an aerobic environment.
One issue with creatine is weight gain; creatine significantly increases weight. This hampers endurance performance. This is seen with multiple forms of creatine and is one reason why some studies show creatine decreases aerobic performance. Still, there are some bright spots. Creatine monohydrate did do a good job in improving running performance and decreasing muscle soreness. Creatine also helped increase the amount of repetitions completed in a high intensity workout.
If you are using creatine while engaging in cardio, there are a few steps you should take:
- Creatine monohydrate probably works best and is the cheapest form to use: 20 grams for 5 days followed by 5 grams thereafter worked best in the second study.
- Use the least amount of creatine possible. More creatine leads to more body weight gains and gastrointestinal discomfort.
- Avoid consuming creatine before engaging in cardio as the gastrointestinal discomfort could hamper performance.
- Izquierdo, M., & Ibañez, J. (2002). Effects of creatine supplementation on muscle power, endurance, and sprint performance. Medicine and Science in Sports and Exercise, 34(2), 332-343.
- Santana, J., & Madureira, D. (2017). Combined effect of creatine monohydrate or creatine hydrochloride and caffeine supplementation in runners’performance and body composition. Revista Brasileira De Prescrição E Fisiologia Do Exercício, 11(70).
- Smith, A., Fukuda, D., Ryan, E., & Kendall, K. (2011). Ergolytic/Ergogenic Effects of Creatine on Aerobic Power. International Journal of Sports Medicine, 32(12), 975-981. doi:10.1055/s-0031-1283179