Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

Markets continue their up-and-down October with another big fall today, and the Dow Jones Industrial Average (DJINDICES:^DJI) kicked off the day in the red and hasn't been able to turn things around. As of 2:35 p.m. EDT, the Dow sits about 120 points lower, with most blue-chip stocks losing ground. Around the health care sector, UnitedHealth (NYSE:UNH) has lost 1% so far, while Johnson & Johnson (NYSE:JNJ) is making the most of a bad day after announcing earnings before the bell. Did health care's biggest name beat expectations? Let's catch up on what you need to know about the Dow's health care stocks.

Johnson & Johnson makes the cut
Johnson & Johnson's stock has only gained about 0.4% today, but that's good enough to rank it among the best performers on the Dow so far. Unsurprisingly, it was J&J's fast-growing pharmaceutical business that helped the company top analyst forecasts for the third quarter. J&J's $1.36 diluted earnings per share beat the Street's projections by $0.04, and the company also managed to hike revenue by more than 3% to $17.6 billion.

That paled in comparison to what Johnson & Johnson managed to accomplish in its drug segment. This business raked in 9.9% sales growth year over year for the quarter, a big boost that pushed the segment past J&J's medical-device division to become its largest business by revenue. Remicade, Johnson & Johnson's immunology mega-blockbuster, continued to record growth in the third quarter as fast-growing up-and-comers such as Zytiga and Stelara sustained their recent upward momentum.

Things weren't so rosy in J&J's other divisions. The company's consumer health segment, its smallest by revenue, grew sales by only 0.8% this past quarter. The consumer business isn't a high-growth one, and while that number is unremarkable, it's not unexpected. Johnson & Johnson's medical-device division, formerly its largest segment by revenue, saw sales fall 2%. The company's big acquisition of orthopedics leader Synthes has propelled the device segment to strong growth recently, but now that the synergies of that buy are tapering off, J&J is experiencing the same headaches that the device industry has faced in an era of falling prices and stiff competition.

Still, the results were enough to prompt J&J to push its full-year earnings expectations slightly. This company's still a great pick for any investor, from first-time stock pickers to experienced market veterans.

Meanwhile, UnitedHealth is on the downswing as Obamacare continues to divide Washington. However, investors need to focus on a more immediate sign of how this insurance leader is doing. UnitedHealth reports its own earnings on Thursday, which will indicate just how this giant is standing among its peers before health-care reform comes into full effect.

Obamacare won't affect Thursday's earnings much, as UnitedHealth has done a good job picking and choosing what state exchanges it will enter. The company has already avoided numerous states, as both it and Aetna (NYSE:AET), a top rival in the insurance market and the third-largest publicly traded insurer, pulled out of California's individual state exchange. For Aetna and UnitedHealth, the blow won't be big: Size matters in this industry, and the larger insurers have a cushion to work with if Obamacare starts off poorly.

Investors need to watch what kind of subscription growth UnitedHealth can post. The company's succeeded in driving its premium revenue and member base higher in recent quarters, and analysts expect revenue at the company to jump nearly 13% year over year for the quarter. Keep your eyes open later in the week.