Lunchtime, or noon to 2 p.m., came in a close second, cited by 29 percent of respondents. The most productive time of day appears to be the morning. Only 17 percent said 8 a.m. to 10 a.m. was unproductive, and only 2 percent said 10 a.m. to noon.

"During a typical workday, employees must juggle meetings, deadlines, phone calls, email, questions from colleagues and unforeseen interruptions," according to Accountemps Chairman Max Messmer. "Individuals who are well attuned to their work habits and routine obligations can better schedule their time and avoid suffering productivity slowdowns later in the day."

Messmer offers the following tips for avoiding the afternoon lull:

• Planning makes perfect. Don't delay difficult activities until the end of the day, when your energy and enthusiasm may wane. Use this time to catch up on basic tasks such as filing, responding to routine emails, updating contact lists and organizing files.
  
  
• Get a breath of fresh air. Periodically stretch or take a short walk to refuel your energy. Enjoy your lunch outside. Even a few minutes away from your desk can help you recharge and be more productive.
  
  
• Food for thought. Missing meals is a recipe for malaise. No matter how busy you are, remember to make time for a complete meal midway through the day and nutritious snacks in between.
  
  
• Take a mental break. Putting work issues out of your mind for even a few minutes can provide the boost you need to finish the day on a strong note.

The national poll by Accountemps surveyed 1,500 finance, HR and marketing senior executives.