Best Thermal Tops

You can keep your tropical sunshine, melting Tarmac and chilled energy drinks. We are just about to enter the best time of year for running. While the rest of the population chucks another log on the fire, wraps itself in a duvet and sips from a steaming mug of hot chocolate, we get to see the seasons change, enjoy empty morning streets and experience an unmatched post-run feel-good sensation.

Of course, the fire, the duvet and chocolate may sound far more appealing than running in winter because, basically, winter is cold. Don’t let that put you off. Pull on one of the base layers tested here, and you’ll barely notice the chill in the air.

We generate a lot of heat when we run – about the same wattage as a one-bar electric fire – no matter what the outside temperature. If all of this heat is allowed to dissipate, we’ll get cold, so a good base layer will keep some of this warmth in. It’ll also let some of it escape, too, as it is surprisingly easy to overheat, even in sub-zero temperatures.

You’ll notice that the fabrics used in most of these base layers are surprisingly similar to those used in summer kit. Whatever the temperature, you need kit made of lightweight material that wicks, that is, draws moisture away from the skin. In winter, wet fabric next to the skin speeds up heat loss. As with summer kit, synthetic fibres predominate, but you’ll also notice the re-emergence of a natural fibre in our selection of the best winter base layers.

Wooly Warmth…

You rarely see sheep shiver. That’s because as well as wicking, wool stays warm when wet…

Icebreaker Skin – £35
Hot spots: 100 per cent merino wool. It is light and wicks, but also helps warm droplets trapped in fibres. Seams aren’t flat, so they could chafe, and, despite the manufacturer’s claims, it feels a little scratchy.
Contact: 01926 339388; www.lockwoods.com
Odlo Synergy – £39
Hot spots: The mix of polyester and merino wool works well. It’s comfortable, wicking and warm, with none of the scratchiness found in the 100 per cent woolen goods.
Contact: 01250 873863; www.odlo.com

Ortovox Lanatex 100 – £35
Hot spots: 100 per cent pure new wool. The thickest and heaviest top here, and very warm. Has flat seams, and a longer back to warm your backside. But it is still a little itchy.
Contact: 01943 461474; www.facewest.co.uk

Snug Warmth…

The closer fitting a top is, the more heat it traps next to the skin…

Asics Motion Jersey – £50
Hot spots: A multi-panelled, tight-fitting, stretchy base layer. Brushed lining means it sits very comfortably next to the skin, and it also has reflective piping for the dark mornings and evenings.
Contact: 01925 241041; www.asics.co.uk

Helly Hansen Lifa Sport Dynamic Crew – £25
Hot spots: A very snug fit, and it really does feel like a ‘second skin’. Great wicking properties and very warm. The sleeves have thumb-holes, but the material feels very synthetic and isn’t especially soft.
Contact: 0115 960 8797; www.hellyhansen.com

Peak Performance Base Long Sleeve – £35
Hot spots: Soft, figure-hugging, very stretchy fabric is brushed inside for extra comfort and warmth.
Contact: 0800 389 8655; www.peakperformance.com

Technological Warmth…

Whatever nature can do, we usually try to improve on it. And sometimes it works…

Lowe Alpine Seamless Long-sleeve – £35
Hot spots: Completely seamless around the torso, which means no chafing. Soft, stretchy and comfortable. And depending on gender, areas of extra ‘wickability’ are woven into the fabric.
Contact: 01539 740840; www.lowealpine.com

Mizuno Breath Thermo Half Zip – £30
Hot spots: Breath Thermo fabric acts like wool, and warms moisture as it draws it away, but Mizuno claims that it is three times more effective than the natural fibre. A lightweight base layer, with soft brushed inner and, thankfully, no itching.
Contact: 0118 936 2100; www.mizunoeurope.com

Salomon Biosensor Zip Neck – £40
Hot spots: Silver ‘X-Static’ thread is anti-bacterial, anti-odour and helps regulate temperature. A very soft and comfortable top, with thumb-holes on the arms to keep hands warm.
Contact: 0800 389 4350; www.salomonsports.com

Comfortable Warmth…

There’s little point being warm if you’re uncomfortable…

Adidas Galaxy Long Sleeve – £20
Hot spots: Lighter and looser fitting than most of the tops here. The thin, soft-to-the-touch fabric isn’t the warmest, but great for days when it isn’t cold enough for a thermal, or warm enough for a short-sleeved shirt.
Contact: 0161 419 2500; www.adidas.co.uk

Insport Thermagrid 50 Trainer – £46
Hot spots: Soft, brushed internal fleece ‘grid’ lifts the fabric off the skin creating pockets to trap warm air. This lightweight top manages to feel very cosy.
Contact: 01827 383200; www.insport.com

Nike Dri-fit Flex Long Sleeve – £35
Hot spots: A tight, breathable and brightly coloured top. Flat seams and multi-panelled construction means the Flex fits beautifully and moves with you. It also has effective reflective detailing on arms.
Contact: 0800 056 1640; www.nike.com