So I've read a few people talking about this issue.
It is a good idea for general fitness to do some lower intensity workouts alongside your regular higher intensity workouts and also for those who do long distance cycling, most of your workouts are low intensity.
The problem is that lower intensity exercises don't seem to be 'rewarded' much with Garmin, so far as I can see. For example I went on a 20 mile easy ride and got a load of 10. I often get a higher load just warming up before a run/workout. My understanding is that load is representing how hard it is for your body to recover from the workout? If so, the metric is inaccurate for lower intensity workouts. I've seen plenty of other examples over longer.
So if I have misunderstood how to interpret load, is there a better way of monitoring how much exercise I've been doing? I'm currently using load as a means of determining whether I am doing too much or not enough to increase my fitness, but it is discouraging me from doing lower intensity exercise which I don't think is helpful.
I do want to also mention that Garmin must be using load in the way I thought because training readiness and training status depends largely on it. My training readiness is currently high and my load ratio is low, because I dared to go on a low intensity ride. (I know 20 miles isn't that long, but I'd get similar load of it was a 50 mile ride). I would certainly not describe my training readiness as high right now! 
I think, for me at least, Garmin can easily lead me to overtrain if I pay too much attention to the metrics.