while that's common mantra, you are better off taking a deep breath before the lift, decending and holding the air until you are most of the way up at least, then exhaling all the way at the top of the lift, taking a nice deap breath in/out, then repeating... Holding hair causes your lungs to expand, your diaphram compacts your internal organs which push against the walls of the abdominals, which push back (even more so if you have a properly fitting belt) thus increasing intra-abdominal pressure. This deloads the spine reducing incidences of injury and increasing core stability which translates into bigger lifts.
The tracers are probably a sign that your blood pressure is very high, the amount of oxygen used from your breath is generally very small, less than 20%. I also doubt it's a sign of high carbon dioxide concentrations as the majority of co2 produced is during the TCA cycle, little is produced during glycolysis (which is primary operative pathway during short sets of heavy squats). If this is consistent you might want to have your blood pressure checked - mine went up to 160/80 recently
need to get some catopres till I get off the gear.