Whether you’re a seasoned athlete chasing a personal best or someone just starting out on a fitness journey, your DNA has a surprising amount to say about how your body performs. At DNA Tests Direct, our DNA Fitness Test analyses key genetic variants that influence everything from sprinting speed to injury risk.

Here’s a look at the science behind it.

Power and Speed: Are You Built to Sprint?

Some people seem naturally gifted at explosive, high-intensity activities. Part of that comes down to three key genes.

• AGT: Encodes the angiotensinogen hormone, which plays a role in blood pressure regulation and muscle growth. A common variant in this gene has been shown to influence athletic power ability, affecting how effectively your muscles perform under intense conditions.
• IL6: Produces interleukin-6, a messenger molecule involved in bone and muscle growth and in managing inflammation after injury. A particular variant of this gene has been linked to increased muscle mass and is found more frequently in Caucasian male athletes who excel in power sports, particularly weightlifting.
• ACTN3: Perhaps the most famous of the trio, often called the “speed gene” or “sprinter gene.” It encodes a protein found in fast-twitch muscle fibres, the fibres responsible for explosive power. A common variant prevents the body from producing a fully functional version of this protein, which can reduce fast-twitch muscle development and, in turn, affect performance in high-intensity sports.

Endurance: Going the Distance

If you’ve always found long-distance running or cycling more natural than explosive sprints, your genes might explain why. Several variants influence endurance ability and aerobic capacity.

• ACE: Regulates blood pressure and fluid balance. Its well-studied insertion/deletion variant is particularly relevant for endurance athletes. The insertion variant leads to lower enzyme levels and greater muscle efficiency.
• ADRB2: Encodes a receptor that interacts with epinephrine to control smooth muscle relaxation and energy balance. A variant of this gene is associated with improved endurance ability.
• PPARA and PPARD: Both encode receptors involved in energy metabolism and gene activation. PPARA is expressed at higher levels in slow-twitch (endurance) muscle fibres compared to fast-twitch ones, and variants in both genes influence the ratio of these fibre types.
• VEGFA: Produces a signalling protein that stimulates the growth of new blood vessels and helps maintain oxygen supply to tissues during exercise.

Aerobic Capacity: How Well Do You Respond to Training?

The PPARGC1A gene is involved in metabolism and muscle fibre formation. A variant of this gene influences how much aerobic capacity you can gain from endurance training, meaning that two people following the same programme may see quite different results based on their genetics.

Lactate Transport: The Energy Myth, Explained

Lactate is often mischaracterised as the villain behind muscle soreness, but recent research tells a different story. During intense exercise, your muscles convert pyruvate to lactate as an alternative energy source, and lactate can actually stimulate mitochondrial growth, making your cells more efficient over time.

The MCT1 gene encodes the transporter responsible for moving lactate into muscle cells. A common variant reduces this transport capacity, which in Caucasian males has been associated with reduced ability to sustain high-intensity exercise such as circuit training, and with lower overall athletic endurance.

Exercise Motivation and Tolerance

Staying active isn’t just about physical capability. Mental factors matter too.

• BDNF: Encodes a brain protein that plays a role in energy balance and motivation. Individuals with a particular variant experience lower perceived exertion and a more positive mood during exercise.
• CRP: Encodes C-reactive protein, which is involved in inflammation. Lower baseline CRP levels are associated with better exercise tolerance and faster heart rate recovery after exertion.

Injury Risk: Protecting Your Connective Tissue

No fitness plan works if you’re always sidelined by injury. Two collagen genes are particularly relevant here.

• COL1A1: Encodes a key component of type I collagen, found throughout the body’s connective tissues. A variant in this gene alters collagen structure and is associated with a reduced risk of soft tissue injury.
• COL5A1: Is involved in fibrillar collagen type 5, which affects flexibility and tendon integrity. One variant has been specifically linked to an increased risk of Achilles tendinopathy, a painful condition involving swelling and stiffness of the Achilles tendon. Understanding your risk here can help you take preventative steps before problems develop.

Pain Tolerance: How Much Can You Handle?

Pain tolerance varies considerably between people, and genetics is one factor that helps explain why. The COMT gene encodes an enzyme responsible for breaking down neurotransmitters such as dopamine and epinephrine in the brain. A well-studied variant in this gene influences how much chronic pain a person can withstand. Interestingly, individuals with the higher pain tolerance variant may actually require higher doses of morphine if pain management is ever needed, illustrating that this genetic trait cuts both ways.

What Can the DNA Fitness Test Tell You?

Our DNA Fitness Test analyses all of the genes described above, giving you a detailed picture of your natural athletic profile. Understanding your genetic strengths and limitations won’t define you, but it can help you train smarter, reduce injury risk and make more informed decisions about the type of exercise that suits you best.

Ready to find out what your DNA has to say? Explore the DNA Fitness Test here.