Are these good for running and heavy sweating?

Yes. The IPX7 rating means they tolerate sweat, rain and even a rinse, and the hooks keep them seated during runs. That is a step above the IPX4 many sport rivals settle for.

How much battery life do they actually give?

The 23-hour figure is total playtime including the charging case, not a single charge. That is on the low side for sport earbuds, so heavy users will recharge the case more often than with 30-hour rivals.

Is the noise cancelling good enough for a gym?

It cuts steady gym noise and street hum, but it is not as deep as premium in-ears or over-ear headphones. Treat it as useful reduction rather than silence.

Will they stay in during burpees and sprints?

The hook design is the main reason to pick these. Owners report they hold through runs and lifting, though the tight fit can press on the ear over long sessions.

Can I take calls with them?

Yes. There is a built-in microphone, and background noise activation is listed, so calls work for short conversations. Sound quality on calls is fine for casual use, not for important meetings.