Karura cycling

How accurate is the VOX max measure by garmin?Almost done with 60kms of cycling at Karura and the damn watch is saying my Vox max is 38 classified as poor.How cannot drop by 10points within a span of 6days?Anyone has experienced hii upuss?

watch yako ile ya garmin bado inashika battery ama ulibadilisha?

Nilibadilisha.Kuna sports shop flani moi avenue diamond bazaar building niliwai garmin forerunner 45 for only 14k.Mali saffi saidi.