While durable, most synthetic fibres are also sensitive to heat and oil and will lose their structure when exposed to high temperatures.
Spandex is a popular fabric in gym and yoga wear, with a smooth, stretchy fit and good shape recovery. Its elasticity can be irreversibly compromised by heat, and is best washed on a delicate setting and dried at low heats.
Similar to Spandex, lycra appreciates a delicate cycle. Its elasticity, while perfectly suited for exercise, can make it particularly susceptible to losing shape in the centrifugal force of the dryer.