It is not always necessary for an athlete to complete both a VO2 max test and a lactate threshold test, and understanding the purpose of each can help athletes decide which one is more appropriate for their goals. Both tests provide valuable, yet distinct, insights into an athlete’s endurance capacity and training needs.

The VO2 max test reflects an athlete’s aerobic capacity and is often used as a benchmark for endurance potential. It’s most appropriate for those athletes who want to assess their overall aerobic fitness and compare it to norms, or to use it for monitoring personal progress. It can also be used to set training intensities by defining different zones that are based on percentages of Vo2 max (i.e. 60-70% for endurance work, 80-90% for threshold work).

The Lactate Threshold test determines the point during exercise at which lactate begins to accumulate in the bloodstream faster than it can be cleared. This threshold indicates the highest intensity at which an athlete can sustain aerobic exercise without rapid fatigue. This test is appropriate for those runners who utilize heart rate zones when training, and who want to improve sustainable pace and performance at race intensity. Compared to the VO2 max test, the Lactate Threshold test guides training intensity more precisely since it directly measures the athlete’s metabolic responses to exercise.

Depending on your training goals, it may be appropriate for you to complete both a VO2 max test and a Lactate Threshold test. VO2 max gives you an overall measure of aerobic capacity, while lactate threshold tells you how much of that capacity you can actually use efficiently during a race. Athletes who complete both tests can use the VO2 max score to monitor their aerobic capacity, and can use lactate threshold to improve sustainable pace and endurance performance.

VO2 Max Test 

Summary: The VO2 max test is the gold standard for determining your aerobic capacity. It is defined as the maximum amount of oxygen that one can consume during exercise. The most accurate way to measure your VO2 max is to perform a graded exercise test to the point of exhaustion in a lab setting that utilizes a metabolic cart. During the test, the athlete wears a mask connected to a metabolic cart. The metabolic cart measures oxygen consumption, carbon dioxide production, the respiratory exchange ratio (RER) (which indicates the type of fuel- carbohydrates or fats- being utilized by the body), workload (METS), and ventilation of the athlete during exercise. Additionally, the rate of perceived exertion (RPE) and heartrate are also recorded by the lab technician during the test. After a 5–10-minute warm-up of light jogging, the intensity of the athlete’s exercise is gradually increased until the athlete reaches a point of exhaustion. Because the athlete is encouraged to run until complete exhaustion, the athlete wears a safety harness during the test that will support the athlete’s weight and prevent injury from a potential fall once exhaustion is achieved.

Benefits: Understanding your VO2 max helps you determine whether your training regimen is optimal, it enables performance monitoring, and it helps determine if you are adequately prepared for endurance events. The VO2 max informs the athlete of his or her aerobic capacity, metabolic efficiency, and overall fitness level.

Resting Metabolic Rate (RMR) Test

Summary: An RMR test offers a noninvasive and precise method for calculating the daily calories required to sustain an athlete’s present body weight. During the test, the athlete sits comfortably in a reclined chair for 20 minutes before starting the test to achieve a true resting state.  The athlete wears a mask connected to the metabolic cart. After 20 minutes, the metabolic cart will begin measuring VO2 and VCO2 for an additional 20 minutes. The athlete should remain as still as possible, breathe normally, and avoid talking or moving during the test.

Benefits: It can be difficult for active individuals to maintain or gain muscle, especially while training for an athletic competition. Measuring one’s RMR is a beneficial first step in determining how many calories are needed to sustain one’s current weight and muscle mass. Also, RMR is a useful tool in helping those who want to either gain muscle or lose weight.

Lactate Threshold Test

Summary: Using heart rate zones (HRZs) helps athletes train effectively. Since heart rates vary widely, the best way to find an athlete’s HRZs is through a lab-based lactate threshold test. This test measures when the body shifts from burning mostly fat to mostly carbohydrates and when lactate starts building up in the blood. 

There are two key points: 

- LT1 (Aerobic Threshold): The point where the body shifts to burning mostly carbohydrates and lactate starts to accumulate slightly but can still be cleared. This is the highest intensity that can be sustained for a long time without major fatigue. 

- LT2 (Anaerobic Threshold): The point where lactate builds up faster than it can be cleared, leading to inevitable fatigue. 

During the test, the athlete wears a mask connected to a metabolic cart that measures breathing and other indicators. The test starts with a warm-up, followed by running at an easy pace that gets progressively harder every 3 minutes. Blood lactate levels are measured at the end of each stage by a small finger prick. The test continues until the athlete reaches their lactate threshold, usually around 85-90% of their maximum effort. 

Benefits: The LT1 and LT2 results are the gold standards used when setting heart rate zones, which help create a personalized and highly effective training program.