All the different terms, features and specs of headlights for trail running training can be a minefield! Here’s a simple guide on what to look for when buying a headlight.
This is a measure of brightness. For running, 200 lumens minimum but 300+ lumens is advisable.
Lighter is better but often reduced weight will mean compromising on battery life. Also note whether the headlight only has a forehead component or if the weight is split between forehead light and rear-mounted battery pack (usually heavier but more balanced). For running, a forehead mounted headlight of less than 100g is advisable.
Rechargeable vs replaceable (eg. AA/AAA). Rechargeable can be topped up between runs to keep it full, replaceable can be changed mid run if it dies (assuming you carry spares). Unless you’re running overnight (ie. Ultramarathon/overnight races) , rechargeable is more practical and cost effective.
This can be deceptive (as it’s measured differently for older headlights) but generally speaking, longer run times are better. If you’re only using it for 60-90min sessions, it won’t matter too much. Compare lights with their run times at similar lumens. For training sessions, a battery life of 3hrs at 300-400 lumens is adequate however 4-6hrs+ is preferable.
This refers to your control of brightness. Some headlights have on/off only, some have high/mid/low power and some have variable brightness. Get one with different power settings (not just on/off) and look at the lumens for each setting. Avoid headlights with extra bright “high” settings and very low “mid” settings (eg. 1000 lumens on high and 150 lumens on mid). Ensure the headlight has a power setting around 250-500 lumens.
This is how the headlight controls the brightness as the batteries run down. Some headlights slowly due, getting dimmer as the battery dies. Other types maintain their brightness until the battery is almost out. The second type is preferable – the headlight features will refer to a low battery warning (the light usually flashes) for this kind of power regulation.
This refers to how wide the light is angled. Some lights have beams that can be adjusted, some have different parts of the light for narrow and wide beam (ie. Two separate lights on the one headlight) while most have fixed beams. While an adjustable beam is good, it adds bulk to the headlight. Ideally a light with a narrow and wide beam option is most practicable for trail running.