Interval training — alternating short bursts of hard effort with rest — is the basis of most modern conditioning workouts. The hard part usually isn't the exercises, it's the timing: watching a clock mid-set is awkward, and a phone stopwatch app forces you to keep glancing at a screen you can't really see while moving. An audible timer solves that: you listen for the bell and move.
The right ratio depends on what you're training for:
| Ratio | Typical use |
|---|---|
| 1:4 (e.g. 20s work / 80s rest) | Max-effort sprints or power work — full recovery between reps |
| 1:2 (e.g. 30s work / 60s rest) | High-intensity intervals with partial recovery |
| 1:1 (e.g. 40s work / 40s rest) | Classic HIIT — challenging but sustainable across many rounds |
| 2:1 (e.g. 40s work / 20s rest) | Tabata-style protocols and conditioning circuits |
As a rule of thumb: the harder the effort, the more rest it needs relative to the work. A max-effort sprint needs a much longer recovery than a moderate-pace circuit station.
"Tabata" gets used loosely to mean "short, intense intervals," but the original protocol — named after researcher Izumi Tabata, who studied it with speed skaters in the 1990s — is specific: 20 seconds of near-maximal effort, 10 seconds of rest, repeated for 8 rounds, for a total of exactly 4 minutes. It's brutal precisely because there's so little recovery between rounds — it's meant to be done at an intensity you genuinely can't sustain much longer than four minutes.
A circuit is a series of stations — different exercises — done back to back, usually for a fixed time per station rather than a fixed number of reps. This is where a repeating interval timer earns its keep the most: set the interval to your station length (say, 45 seconds work / 15 seconds transition), start it, and move through the whole circuit without stopping to check anything. The bell tells you when to switch.
LoopBell's Interval Timer rings on a fixed gap you choose, with adjustable volume and beep count, so you can hear the transition without staring at a screen. Set it once, hit start, and move.