In reply to Bert:
There are essentially two ways to approach base-layers; those that wick well, dry fast and are light weight (synthetic) and those that are more comfortable, warmer and do not retain odours (merino).
Given that you are engaging in higher intensity activities you will need a base-layer which will wick better than merino and dry faster. The best base-layers for your intended activities are the Rab MeCo base-layers which use a third coco fibres and two thirds merino fibres. The coco allows it to dry significantly faster while the merino prevents the build up of odours and maintains comfort.
If i were you I would avoid pure merino if you find you're sweating alot as it is unlikely to be able to cope with the amount of moisture being created and will eventually become clammy and cold especially when moving from high to low intensity activities, for example going downhill on the bike after a long climb.
I generally use merino for climbing, walking and mountaineering, and MeCo for cycling. Hope this helps!