References

An almond-shaped structure deep in the brain controls people's feelings of hunger and fullness in an attempt to keep them at a constant body weight. In obesity, its signaling can be disrupted.

BUYING GUIDE These are the best running watches in every category, from Garmin Fenix 7 to Apple Watch Series 8 and Coros Pace 2.

Buying Guide These are the best fitness trackers you can buy in every category, from Apple Watch Series 8 and Garmin Fenix 7 to Amazfit Balance.

Buying Guide These are the best electric toothbrushes for kids, from Oral B Kids and Philips Sonicare for Kids to AutoBrush Sonic Pro.

Buying Guide These are the best rowing machines you can buy in every category, from Concept2 RowErg and Ergatta Rower to Hydrow Wave.

Reference We take a closer look to see if using air purifiers helps with asthma.

REFERENCE Air purifiers can improve air quality, but do these devices help relieve allergies?

REFERENCE We pit air purifiers against ionizers to get to the bottom of what each appliance really does.

Reference Air purifiers are intended to remove pollutants from the air, but how well do they really work?

REFERENCE Can air purifiers help with dust and dust mite allergies?

The use of "anno domini" and "before Christ" to mark time began in the early days of Christianity, when clerics needed to know when Easter would fall.

Buying Guide These are the best electric toothbrushes you can buy in every category, from Oral-B Genius X and Bitvae R2 to Waterpik Complete Care 9.0.

These are the best Garmin watches you can buy in every category, from Fenix 7 and Forerunner 265 to Venu 2 Plus.

BUYING GUIDE The best Fitbit wearables available to buy: Tried and tested to provide you with options from simple fitness trackers to feature-packed smartwatches.

These are the best budget fitness trackers you can buy in every category, from Fitbit Inspire 3 and Garmin Vivosmart 5 to Amazfit Bip 3 Pro.

BUYING GUIDE These are the best treadmills you can buy in every category, from NordicTrack x22i and Mobvoi Home Treadmill to Peloton Tread.

These are the best walking treadmills you can buy in every category, from Mobvoi Home Treadmill to Bluefin Fitness Task 2.0 Treadmill.

BUYING GUIDE The best cameras for wildlife photography have impeccably accurate autofocus, a fast burst rate and sharp, detailed images — we've rounded up the best models.

BUYING GUIDE These are the best air purifiers you can buy in every category, from Levoit Core 600S and BlueAir Blue Pure 411i Max to Dyson Purifier Cool.

BUYING GUIDE The best star projectors bring the wonders of the cosmos into your home — find the best models here so you're ready for Amazon Prime Day.