Helos do it all the time....
Part of the start-up procedure for an R22/R44 is to allow the engine to warm up.
After starting the engine (and letting the clutch engage), the engine is run up to 75%-80% operating ERPM and held there whilst the temp climbs into the green. This can take a few minutes on a cold day. Once there we carry on with the engine checks (magneto's, carb heat, needle-splits, etc.)
Note the engines are de-rated, so that even at 100% ERPM its still only about 80% of what the engine is capable of....