Headlamps serve two purposes for runners: They help illuminate the trail or pathway you're running on, and they also make you more visible to drivers, cyclists and other runners along the way. If you're running on dark trails, you'll need a fairly bright headlamp that gives you enough range to anticipate and avoid obstacles; but if you're running in the city, you can afford to focus more on finding a lamp that's light weight and compact, while still being bright enough to make yourself seen and get you through spots between street lamps or other illumination.
For trail runners -- and urban runners too -- our best-reviewed running headlamp is the Black Diamond Sprinter (Est. $80). Users love that it has runner-friendly features like a red strobe taillight (which you can turn on and off) and a rear battery pack that puts the heaviest part of the light behind you, so the headlamp never slides down or bounces around on your forehead.
Black Diamond's PowerTap technology -- which backcountry hikers and campers seem generally ambivalent about -- really comes into its own for runners; they love being able to tap the side of the casing to quickly set the headlamp to maximum intensity when near vehicles or fast-moving bikes, then tap it again to return to the previous setting. The Sprinter's lithium polymer battery charges (via a USB port) in 5 hours and provides at least that much run time at max lighting (130 lumens, with a max distance of 30 meters).
That's not enough time for serious backcountry use, but it's plenty for most runners, especially if at least part of your run takes place during daylight. Also, Outside's "Gear Guy," Doug Gantenbein, says that on the low setting (which reduces throw distance to 2 meters), he's able to get more than 60 hours of use from a single charge on the previous version of the Sprinter. (The manufacturer only advertises 42 hours of runtime on low.) This little headlamp only weighs 105g (3.7 ounces).
The Sprinter also receives a "top pick for runners" award from OutdoorGearLab.com, an editor's choice award from Trail Runner magazine, and a nod from Jacob Waltz with GearInstitute.com. Waltz says the Sprinter stays put even without the use of the optional top strap, and it's comfortable when worn as a waist light. The Sprinter is rated as "stormproof" (IPX4); it can withstand rain and sleet from any angle, and it's regulated for constant illumination, even as the battery runs down.
If you're a hardcore backcountry runner that spends a lot of time in the dark, you'll probably prefer the Black Diamond Storm (Est. $50), our best-reviewed weatherproof headlamp. It's completely sealed and waterproof, and produces regulated light, with a max power of 250 lumens and a max range of 80 meters. Its run time is closer to 8 hours on the high setting, and you can swap out the four AAA batteries if you need continuing light.
If you do most of your running in urban settings or are looking for a small, dependable headlamp without all the high-tech bells and whistles, consider the 90-lumen Princeton Tec Sync (Est. $30), our best headlamp for urban runs. It's small, lightweight (58g/2 ounces), and has a dial for selecting lighting modes instead of a button. (Options include a red LED and a lockout mode to keep the headlamp from turning on in your pocket.) Users either love that dial or they hate it; those that aren't fans say it takes two hands to operate and is the part most prone to failure.
With that said, the Sync draws heaps of expert praise from the likes of TrailandUltraRunning.com and Trail Runner magazine and Backpacker magazine. "It's as simple and intuitive as it gets, yet still has all the features we want" writes Kristen Hostetter with Backpacker. It also gets a "Best in Class" award from GearInstitute.com, where the writer, Jacob Waltz, says it's comfortable to wear and doesn't bounce when you run. It's not necessarily the best choice for bad weather, though, as the manufacturer doesn't release water- or dustproofing specs, and we see reports that bad weather can short out the dial switch.
The Sync runs on three AAA batteries; the manufacturer promises 75 hours of burn time on max power (58m max range), or 200 hours on low power. Testers with Backpacker got about 70 hours out of it on max brightness before it became too dim to use -- but note, that's not the same as having 70 hours of actual maximal performance; because the Sync doesn't provide regulated lighting, the brightness dims as the batteries fade.
If you are a fan of high-tech or "smart" headlamps, the best in the market right now is the Petzl NAO (Est. $185), which has a reactive lighting feature that automatically adjusts the beam to match ambient light conditions and the distance to your target. It still has a few bugs to work out -- for example, testers with OutdoorGearLab.com say that campfires, other headlamps and even reflective surfaces can confuse the reactive lighting feature and cause it to flicker annoyingly.
They also say they got an abysmal battery life from the Petzl NAO -- about 2 hours on the max brightness, and 113 meters of reach. Still, with up to 430 lumens of light in constant mode (AKA manual control) and a maximum of 575 lumens in reactive lighting mode, this headlamp's bright, even beam earned the only perfect trail finding score in the OutdoorGearLab.com tests.
The NAO has a few other nice features: An optional belt kit lets you move the battery pack to your waist to keep it warm, and the rechargeable lithium-ion battery pack can be replaced with two AAA alkaline or lithium batteries. It also has the usual lockout function to preserve battery life while in your pack. If you're willing to spend a little quality time with the headlamp's instructions and Petzl's free downloadable "OS by Petzl" software, you can also tweak the reactive settings -- in particular, the low light setting -- to better suit your needs. On the downside, it's relatively bulky at 187g or 6.6 ounces.
We imagine that within a few years, this sort of reactive technology will be much more refined and user-friendly. In the meantime, if you prefer a simple, straightforward headlamp, any of the other models in this report are excellent.