You track your training, your nutrition, your sleep, and your recovery. Your blood is the one dataset that tells you whether all of it is actually working. Here is what serious athletes should test and why most "sports" blood tests barely scratch the surface.
Typical sport and performance panels check testosterone, cortisol, iron, vitamin D, and basic inflammation. Maybe 15 to 30 markers. That tells you whether your testosterone is normal and whether your ferritin is low. It does not tell you whether your cardiovascular system is handling the stress, whether your metabolic efficiency is optimal, whether your thyroid is converting properly, or whether your immune function is suppressed from chronic training load.
Professional athletes do not get 20-marker blood tests. Their team physicians run comprehensive panels across every major health system. They test cardiovascular risk, metabolic depth, full thyroid, immune function, and organ health alongside the performance markers. The difference is data resolution. With 20 markers, you are guessing. With 114, you are making decisions.
Testosterone drives muscle protein synthesis, recovery, and adaptation. Cortisol is the primary catabolic stress hormone. The testosterone-to-cortisol ratio is one of the best markers of recovery status and overtraining risk. DHEA-S provides context on adrenal reserve. If your cortisol is chronically elevated and DHEA-S is declining, your HPA axis is under sustained stress, and your testosterone will follow it down. You need all three to see the pattern. Testing testosterone alone is like checking your bank balance without knowing your expenses.
Iron is essential for oxygen transport, energy metabolism, and immune function. Athletes lose more iron through sweat, foot-strike haemolysis, GI losses, and inflammation-driven sequestration. Ferritin is the usual marker but it is an acute-phase reactant. After a hard training block, hs-CRP rises, and ferritin rises with it, masking genuine depletion. Full iron studies (serum iron, TIBC, transferrin saturation, transferrin) give the true picture. A ferritin of 40 with a transferrin saturation of 12% is functionally deficient. A ferritin of 40 with a saturation of 30% is fine. Without the full panel, you cannot tell the difference.
Your thyroid controls metabolic rate, energy production, body temperature regulation, and recovery speed. Athletes with subclinical hypothyroidism experience fatigue, slow recovery, cold intolerance, unexpected weight gain, and reduced training tolerance. A standard TSH check misses conversion problems. Your TSH could be normal while your Free T3 (the active hormone that drives metabolic rate) is low. This is especially common in athletes with high training volume and inadequate caloric intake. TrueVitals tests TSH, Free T3, Free T4, and thyroid antibodies in every panel.
Being fit does not make you immune to cardiovascular disease. ApoB, the best predictor of atherosclerotic risk, is independent of fitness level. Lp(a) is a genetic risk factor that affects 20% of the population regardless of how much they train. Endurance athletes can have elevated Lp(a) and ApoB despite excellent HDL and low resting heart rate. These markers are not about whether you are fit enough. They are about whether plaque is accumulating in your arteries despite your fitness. Test them at least once. TrueVitals includes both from the Ultimate panel.
Athletes who consume high carbohydrate loads can develop insulin resistance without realising it. HbA1c and fasting glucose often remain normal until the problem is advanced. Fasting insulin and HOMA-IR reveal metabolic inefficiency at the earliest stage. For athletes focused on body composition, performance fuelling, or longevity, insulin sensitivity is one of the most important metrics to track. It is also one of the most actionable: diet composition, meal timing, and training modality all influence it directly.
ALT and AST are released during muscle damage, not just liver damage. If you train hard, your ALT and AST will be elevated after a session, sometimes for 48 to 72 hours. A basic blood test flags this as abnormal liver function. A comprehensive test adds GGT, which differentiates: if GGT is normal while ALT and AST are elevated, the elevation is muscular, not hepatic. Without GGT, you get a false alarm. With it, you get context. TrueVitals includes GGT, ALP, bilirubin, and albumin alongside ALT and AST for the full liver picture.
Heavy training temporarily suppresses immune function. Immunoglobulins (IgA, IgG, IgM) quantify this suppression. Low secretory IgA is associated with increased upper respiratory tract infections in athletes. If you are getting sick frequently during heavy training blocks, your immunoglobulins may explain why. Most sports blood tests do not include them. TrueVitals Ultimate does.
Test at the end of a recovery week, not during a heavy block. Cortisol, CK, ALT, AST, hs-CRP, and immune markers are all acutely affected by training. Testing during a heavy week gives you a snapshot of your response to that specific load, not your baseline health. Testing after 3 to 5 days of reduced training gives you a more representative picture.
Fast for 8 to 12 hours, morning draw. Testosterone peaks in the morning and declines through the day. Cortisol follows a similar diurnal pattern. Fasting ensures glucose, triglycerides, and insulin are not skewed by recent meals. Water is fine.
Avoid alcohol for 48 hours before. Alcohol elevates GGT, liver enzymes, triglycerides, and suppresses testosterone. Even moderate drinking the night before can distort several markers.
Test every 6 months. One test is a snapshot. Two tests show a direction. For serious athletes adjusting training, nutrition, or supplementation, 6-monthly testing gives enough data to track what is working and what is not.
Services like Forth sell "performance" and "sport" panels at £79 to £180 with 20 to 45 markers. They check the obvious things: testosterone, iron, vitamin D, cortisol. But they miss the systems that explain why your performance is stalling despite "normal" results.
Testosterone, cortisol, ferritin, vitamin D, B12, cholesterol, liver enzymes, thyroid (TSH only), hs-CRP, full blood count. Tells you if something is obviously wrong. Misses insulin resistance, cardiovascular risk, thyroid conversion, immune suppression, and full iron context.
Everything above plus: free testosterone, SHBG, DHEA-S, LH, FSH, full iron studies (not just ferritin), Free T3, Free T4, thyroid antibodies, ApoB, Lp(a), insulin, HOMA-IR, C-peptide, immunoglobulins, tumour markers, cystatin C, PTH, and 80+ additional markers. Tells you what is actually happening and why.
The price difference is approximately £170. The data difference is approximately 90 additional biomarkers across every major health system. For an athlete who spends hundreds on supplements, coaching, and equipment, the blood test that actually tells you what is working is not the place to cut costs. See our full Forth comparison.
At minimum: testosterone (total and free), cortisol, DHEA-S, full iron studies, full thyroid (TSH, FT3, FT4, antibodies), ApoB, HbA1c, insulin, vitamin D, B12, magnesium, zinc, hs-CRP, and immunoglobulins. A comprehensive panel like TrueVitals Ultimate (114 markers, £349) covers all of these and significantly more in a single test.
ALT and AST are released during muscle damage, not just liver damage. Hard training, especially resistance work and HIIT, can elevate both for 48 to 72 hours. GGT differentiates: if GGT is normal while ALT and AST are elevated, the cause is muscular. This is a normal training response. Test after 3 to 5 days of reduced training for the most representative baseline.
Every 6 months is ideal. Test at the end of a recovery week for the most representative results. Athletes adjusting training, nutrition, or supplementation may benefit from quarterly testing during transition periods.
Light activity is fine. Avoid intense training for at least 48 hours before testing, as it acutely elevates CK, ALT, AST, cortisol, and inflammatory markers. Test at the end of a recovery week for the best baseline. If you do train hard before testing, your report will note which markers may be affected.
TrueVitals tests 114 biomarkers vs Forth's ~45. The additional markers cover cardiovascular risk (ApoB, Lp(a)), metabolic depth (insulin, HOMA-IR), full thyroid (Free T3), immune function (immunoglobulins), and tumour screening. TrueVitals also delivers a 30+ page AI-powered report vs Forth's traffic-light dashboard. For athletes who want to understand, not just glance, TrueVitals provides significantly deeper insight. Full comparison.
114 biomarkers across every health system. The data professional athletes get from their team physicians. AI-powered reporting. £349.
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