Beyond Euglycemia: Case Studies Using Continuous Glucose Monitoring in Elite Athletes Without Diabetes During Record Athletic Events.
Level 4 - case-series / case-control
Descriptive case series of individual athletes.
PubMed 41829603 · doi:10.3390/s26051624
What was done
Continuous glucose monitoring (CGM) was evaluated in a descriptive case series of three non-diabetic elite athletes during distinct record athletic events: an ultra-endurance relay cycling world-record performance (Race Across the West, RAW; lasting 44 h 20 min), an Everesting Challenge cycling record attempt, and a competitive maximal constant-weight no-fins breath-hold depth dive. Measures included mean glucose, standard deviation, time in tight range (TITR: 70–140 mg/dL), time below range (TBR: <70 mg/dL), time above range (TAR140: >140 mg/dL), and ancillary metrics including peak power, heart rate, and blood lactate where available.
What was found
During the RAW challenge, mean glucose was 91 ± 23.2 mg/dL with 9.15% TBR and 35.58% TITR during cycling periods, and 115 ± 24.7 mg/dL with 9.11% TBR and 43.16% TITR during rest. The Everesting cycling attempt exhibited sustained hyperglycemia with a mean glucose of 160 ± 5.7 mg/dL, a CV of 3.5%, and 100% TAR140. Following the breath-hold dive, interstitial glucose during recovery was 187 ± 18.5 mg/dL (100% TAR140) alongside a peak blood lactate of 13.4 mmol/L.
Why it matters
These observations indicate that standard clinical glycemic targets do not reflect normal physiological responses during extreme athletic exertion in non-diabetic individuals. Interpreting athlete CGM profiles requires performance- and context-specific reference frames rather than clinical diabetes thresholds.
Limits
The study is restricted to a very small sample (n = 3) across three heterogeneous sporting disciplines without control participants or standardized nutritional monitoring reported in the abstract. Interstitial glucose lag and sensor accuracy under extreme physiological stress were not evaluated.
Cited by
- supports Working out, particularly for individuals who are fat-adapted, can trigger blood glucose spikes above 140 mg/dL.