Sport and exercise with diabetes
The glucose response to exercise is highly individual. CGM shows it in real time and helps with planning.
What it is
Physical activity is a powerful glucose-lowering tool — but unpredictable. Aerobic exercise usually lowers glucose; anaerobic / resistance work can briefly raise it via catecholamines. Insulin sensitivity stays elevated for 24-48 hours post-exercise, hence "delayed" hypos.
Core rules
Pre-exercise glucose
6.0-10.0 mmol/L — optimal pre-aerobic. < 5.5 — carbs before start. > 13.9 — delay and check ketones if T1D.
Carbs under load
Aerobic > 60 min: 15-30 g of fast carbs every 30-45 min. Adjust by real-time CGM trend.
Overnight basal reduction
After an intense daytime workout, drop overnight basal by 20-30%. Delayed hypo is the most common scenario.
Trend arrow > value
Under load, decisions are driven by the trend arrow, not the value. CGM shows rate-of-change — a finger-stick misses it.
Syai's role
IP28 — handles showers and pool swimming (pressure dives — no). Smartwatch buzz alert mid-run or mid-gym. No need to remove the sensor post-workout — standard 14 days. Fits marathoners and weekend warriors alike.
Studies
ADA Position Statement on Physical Activity and Type 1 Diabetes
Riddell M.C. et al. · The Lancet Diabetes & Endocrinology · 2017
On requestCGM in athletes with type 1 diabetes — practical guidance
Yardley J.E. et al. · Sports Medicine · 2021
On request
Further reading
More on the manufacturer's site
Syai Health maintains a detailed topic page with clinical cases. Opens in a new tab.