The ideal test is a short warm up followed by a gradual increase in intensity until you reach your maximum heart rate. Sounds simple, but damn hard!
I have discovered that using a power meter might be one of the best ways to make the increments in intensity just as smooth as needed. Making small increments of 10 Watts every 30 seconds is a successful approach to attain your maximum oxygen consumption. You might have noticed that I recommend the same strategy for Watt Max Testing.
Typical mistakes when testing Maximum Heart Rate
Starting out too fast
If you start out too fast there is a great risk that you get exhausted before your oxygen uptake is ready to perform at 100%. The reason for this is that your body uses anaerobic metabolites to produce the required energy.
Starting out too slow
If you start out too slow it is very unlikely that you will have the power when you need it. Again you can conclude that pacing strategy is very important for the final result.
Not motivated
If you are not motivated when you perform a maximum heart rate test (or any other physical test) it is obvious that your performance will go down. Try to motivate yourself before the test and have a training partner or personal cycling coach to support you through the whole event.
It is not an easy to job to find your maximum heart rate, but if you prepare a physical test with the tips I have recommended above, there is a good chance that you can make a new personal record.