Under Armour Training Vent 2.0 Short Sleeve Tee - Mens - Academy/White  £23.95

When you're going all out, you need a shirt with lots of ventilation. A shirt that's light, fast-drying, and loose enough to let you power through.
Loose: Fuller cut for complete comfort
Ultra-breathable knit fabric is super lightweight & comfortable
Material wicks sweat & dries really fast
4-way stretch construction moves better in every direction
Dropped, shaped hem for enhanced coverage
Style #: 1361426
96% Polyester/4% Elastane
Machine wash cold with like colors
Use only non-chlorine bleach when needed
Tumble dry low
Do not iron
Do not use softeners
Do not dry clean