HotLog alternatives
HotLog is a careful sauna journal. You record the sauna type, temperature, humidity, duration and Aufguss sessions on your iPhone, and if that is the record you want, it is a good one. If you would rather not type sessions in at all, Contrast times them from your Apple Watch, records heart rate round by round, saves to Apple Health, and on an Apple Watch Ultra or Series 10 and later starts a bath or plunge round on its own.
Side by side
| HotLog | Contrast | |
|---|---|---|
| Apple Watch app | Not listed | Yes |
| Times the session for you | Not advertised | Yes |
| Heart rate | Not advertised | Yes, per round |
| Humidity, sauna type, Aufguss | Yes | No |
| Saves to Apple Health | Advertised | Yes, as a Cooldown workout |
| Price | Paid upfront | Free, with optional Pro |
HotLog column from its App Store listing, checked 2 October 2026. "Not advertised" means the listing does not mention it, not that the app cannot do it.
What HotLog does
- Records sauna, steam, infrared and cold plunge sessions.
- Logs sauna type, temperature, humidity, duration and Aufguss sessions.
- Shows statistics and trends over time.
- Runs on iPhone. No Apple Watch app was listed when checked.
What its low-star reviews keep raising
Recurring themes in its 1–3 star App Store reviews, paraphrased rather than quoted. Each review is one person's experience, and some will describe problems since fixed.
- Everything entered by hand, with no built-in timer, so sessions are timed with something else and typed in afterwards.
- No heart rate.
- Apple Health integration not working the way reviewers expected.
- History not coming across to a new phone.
Where Contrast is different
- Every round is timed from your Apple Watch, so nothing is typed in afterwards.
- Heart rate for each round, with the average, minimum and maximum, wherever the watch can be worn.
- Every session is saved to Apple Health, and Contrast keeps its own copy on the phone, which survives a change of phone.
- On an Apple Watch Ultra or Series 10 and later, bath and plunge rounds start on their own.
Stay with HotLog if
- You want to record humidity, sauna type or Aufguss sessions. For a sauna round Contrast records the time, and an air temperature you type in, and nothing more about the room.
- You use steam rooms or infrared cabins and want them named as such. Contrast calls every dry-heat round a sauna round.
- You have no Apple Watch and want a journal rather than a timer. Contrast can log by hand too, but the watch is where it does its best work.
Common questions
Can Contrast record sauna humidity?
No. For a sauna round it records the duration, heart rate if the watch is on your wrist, and an air temperature you type in.
Can I wear my Apple Watch in the sauna to get heart rate?
Apple advises against wearing any model other than Apple Watch Ultra in a sauna, and against wearing Ultra above 55 °C (130 °F). A traditional sauna runs hotter than that, so for most saunas the round is timed with the watch left outside.
Contrast is not affiliated with HotLog - Sauna & Cold Plunge or Thomas Dori. Their name is used here only to identify their app.