Cold vs Hot Therapy: When to Use a Chill Tub or a Spa

Max Piggott

People have used hot and cold water to feel better for centuries, from Nordic saunas and ice holes to Roman baths. With a Chill Tub and a hot tub, you can do both at home.

So when should you go cold, and when is heat the better choice? Here is how to use each one, and when to pick one over the other.

Cold therapy: Chill Tubs

Cold therapy, also called cold water immersion, means spending a short time in cold water, usually between 4°C and 15°C (39°F to 59°F).

Why people use cold therapy

  • Tired, achy muscles after hard exercise often feel better after a cold dip
  • Recovery: many athletes use it as part of their routine after training
  • An instant wake-up: the cold gets your heart pumping and leaves you feeling alert
  • Mental resilience: getting used to the cold builds confidence and focus

When to use a Chill Tub

  • After intense exercise or sport
  • In the morning to wake yourself up
  • After a sauna, to complete a hot and cold cycle
  • On stressful days, for a quick mental reset

Tip: Start with short sessions of 1–3 minutes and build up gradually. Slow, controlled breathing makes the cold much easier to handle.

Heat therapy: hot tubs

Hot tubs usually run between 37°C and 40°C (98°F to 104°F). The warm water and massage jets help you relax properly.

Why people use heat therapy

  • Eases muscle tension and stiff joints
  • Helps you loosen up, so stretching feels easier
  • Helps you unwind after a stressful day
  • Helps you wind down before bed
  • Soothes everyday aches, such as a sore back

When to use a hot tub

  • Before bed, to unwind
  • In the evening, to relax after a long day
  • When you feel stressed or mentally tired
  • In the colder months, to warm up

Tip: Drink plenty of water, and do a few gentle stretches while the muscles are warm.

Contrast therapy: using both

Contrast therapy means alternating between hot and cold, for example a hot tub soak followed by a cold plunge. Fans of contrast therapy say it:

  • gets your circulation going
  • helps them recover after exercise
  • gives a noticeable lift in mood

A typical routine looks like this:

  1. 10 minutes in the hot tub
  2. 2–3 minutes in the Chill Tub
  3. Repeat for 2–3 cycles

Listen to your body

Everyone is different. What suits a keen runner may not suit someone easing a bad back, so adjust to how you feel. You shouldn't use a hot tub while pregnant. If you have a heart condition or high blood pressure, speak to your GP before trying cold immersion or very hot water. If you are pregnant, speak to your GP before trying cold immersion.

  • Try cold when your muscles are sore or you need waking up.
  • Choose heat when you are stressed, stiff or want to relax.

Hot tub or Chill Tub? Why not both?

Hot and cold water do different jobs, and they work well together. If recovery and wellbeing are a priority, it is worth having both a hot tub and a Chill Tub at home.

At Canadian Spa Company we offer hot tubs and cold immersion tubs for use all year round.

Cold vs hot at a glance

Chill tub Hot tub
Typical temperature 4 to 15°C; the Chill Therapy Spa goes as low as 5°C 37 to 38°C for most adults; 40°C maximum
Session length Start with about 30 seconds; build up slowly 15 to 20 minutes
How it feels Sharp, alert, energising Relaxing and soothing
Popular times Morning, after training Evening, before bed
Main risks Cold shock, hypothermia Overheating, dehydration
Children Always supervised; generally not recommended for young children 36°C maximum for under-12s, always supervised

Three routines to try

Morning wake-up

  1. Short plunge in the chill tub, starting at 30 seconds.
  2. Out, dry off and dress warmly.
  3. Warm drink and a few minutes of gentle movement.

Evening wind-down

  1. 15 to 20 minutes in the hot tub at 37 to 38°C.
  2. Glass of water.
  3. Screen-free time before bed.

Post-training contrast

  1. 10 minutes in the hot tub.
  2. A short cold plunge, within your tolerance.
  3. Repeat for 2 to 3 rounds.
  4. Finish warm and dry off quickly.

Safety

  • Enter cold water slowly and control your breathing.
  • Never plunge alone when you are new to it.
  • No alcohol before either.
  • Get out if you start to shiver hard, feel dizzy or feel unwell.
  • Speak to your GP first if you have a heart condition, high or low blood pressure, diabetes or another medical condition.

Frequently asked questions

Should I start with hot or cold?

Many people start warm so the cold feels more manageable, and finish warm so they are not cold when they get out.

Can I use a hot tub as a cold plunge in summer?

A hot tub cannot chill water. For proper cold-water sessions you need a tub with a chiller, such as our chill therapy spas.

How do I keep chill tub water clean?

See our guide to cold plunge water care.

Interested in cold-water therapy?

See our chill therapy tubs.

Back to blog