I did some research today into why the first 10 minutes of my workout feels so difficult, but after that it feels great. It's largely to do with how the body uses different fuel depending on what stage of the workout you're in and how hard and long you've been exercising for. It's been a long time since I completed my Biology A-Level and Zoology degree, but I hope I've managed to simplify the the science behind the 10 minute wall here. :)
ATP (Adenosine Triphosphate) is an energy-bearing molecule that our bodies require in order to do pretty much everything they do. At rest, we produce the ATP from stored energy reserves from food, primarily via aerobic (oxygen-required) reactions. When we start to work out, our bodies quickly use the available ATP, forcing the body to have to produce more to fuel our muscles. Whilst we can quickly supply a little more by anaerobic respiration (without oxygen), the body has to fully switch on the aerobic reactions in order to sustain the continued work. The '10 minute wall' (in reality, more like 4-5 minutes) comes about due to the delay between using up the easily available ATP and the aerobic reactions producing enough to keep us going, and is otherwise known as the oxygen debt.
The switching from one energy system to the other is generally accompanied by heavier breathing, increased heart rate and muscular discomfort as your body works to get enough oxygenated blood to the muscles to kick off the sustainable aerobic reaction which will allow you to keep working out at a steady pace, at which point your heart rate and breathing should settle, and your workout should usually become a little more enjoyable. By ensuring you perform a gradual warm-up to full-blown exercise, you not only help your muscles to prepare for work, but you should also help yourself avoid the discomfort of the oxygen debt.
Rowing (moderate, 30 spm) = 10 minutes
Cycling (Level 3, 80-85 rpm) = 30 minutes
Shoes: Vivobarefoot Breatho
(Minimus ones currently with New Balance for exchange...)